Since I think I know where Ron is getting his camera lust (after covering Comicon, and with future conventions/events on the horizon), I understand the need for keeping costs down, while also getting something with usable results.
I'm a Canon guy, so that's about all I know, take it for what it is worth.
Just to confuse things more, I went with a cheap $200 refurb EF-S 55-250mm F4.0-5.6 IS Canon telephoto lens for the longer shots at conventions. You can get it for $229 or less at most places.
It is a nice light-weight telephoto lens if you have enough light on the subject. But you trade-off low light shooting capability, though the T2i might help with its higher ISO capabilities.
If you can live without the extra reach of 250-300mm range, you can save $300 with this lens if you go Canon (or the same with Nikon, a la Neil's Nikon lens).
The next step up is to pursue the pricier larger aperture (fast) telephoto lenses that cost a lot, and weigh a ton. Cameron appeared to be using a Canon EF 70-200 F2.8 IS lens at Comicon to pull off the sweet photos he took at the press conferences and panels. It's a heavy lens, any constant "fast" 2.8 (or lower) lenses will be heavy, but if you want the quality, you have to put up with some inconvenience when it comes to toting photo gear.
Plus, you may end up wanting some portable tripod or monopod when it comes to blurry handheld photos if you have to slow down the shutter speed to let in more light to get the shot. IS helps with camera shake, but motion is still motion, and the slower the shutter, the more blur gets introduced.
Since I finally upgraded my walking around wide angle lens to the Canon EF-S 17-55mm F2.8 IS USM lens, my next lens upgrade will most likely be a F2.8 telephoto lens, but I still need to get my head around the cost of such a lens (probably over a grand), and the extra weight of such a beast, too.
Here's a photoset I shot at Dragon*Con last year with the cheapo Canon 55-250mm F4.0-5.6 IS lens:
If you browse around any of the photos, you can check out the settings used if the Exif info is intact with photos posted on photo-host websites. I use Flickr, and I don't strip away my Exif info from my photos, so if you wanted to check out the settings, it's easily done (there's a "More Properties" link on the right hand side of individual photo in the Additional Info section found towards the bottom section of the page). I think it helps to see what a lens is capable of, and knowing the settings used on a given camera model body to achieve a shot that you would like to emulate. For example:
The aperture will change as you go longer with a telephoto lens, so I maxed out mine to 250mm, and the aperture value defaulted to F5.6, which is the widest aperture opening for the lens at that long end (letting in the least amount of light, so you have to compensate with either shutter speed and/or ISO setting, as well as possible Exposure Bias), but you can also make the aperture smaller with camera aperture adjustments. If I'm on the short end of the telephoto, 55mm, the largest aperture I could use is F4.0, though I could use my camera is make my aperture smaller (higher number). But photography is always about light, and the more light your camera lens is capable of letting through, the more you'll be in charge of the quality of the exposure of the photo you're shooting.
Sorry to derail the thread, but I figure if I can save you $300, I'd try it.
BTW, Ron, if you just wanted to buy the Canon T2i body for $799.99, I'll give you my EF-S 18-55mm F3.5-5.6 IS lens that came with my Canon XSi last year, it's just sitting in a box at my house (it's about a $70 lens on Ebay or Fred Miranda). And then if you went with the less expensive Canon 55-250mm telephoto lens for $255 at Onecall, you'd be up and running at $1,055 (but you'd have to buy the camera bag, and other extras). Though you'd probably find yourself upgrading the Canon 18-55mm lens within a year like I did. Haha.
Just remember, the longer the lens, the higher shutter speed you need to avoid blurry photos. And the higher the shutter speed, you'll most likely need to more ISO capability or aperture width to get enough light for a properly exposed shot. Plus, you can crop a photo to get the pertinent image portion for something usable, so the difference between the reach of 250mm and 300mm isn't much, but the cost is more than 2-folds, but not 2 times the reach or benefit, IMHO. Plus, it might be easier to re-sell a $200 lens than a $550 lens. Plus I'd be more apt to put that $300 saved towards my next lens upgrade. Tee-hee.
From reading the specs on the kit lens, I think it's the same EF-S 18-55mm IS lens in either kit for the XSi or T2i. Both camera models are EF-S crop bodies. It's a starter lens, but once you want to shoot with less light, or want more bokeh (the fuzzy backgrounds that comes shallow depth of field that wider aperture offers, which brings the close-up subject of interest into focus while the background fades away), or go flash-less for low-light conditions for more natural-looking shots, then you end up looking for "faster" (but heavier) lenses. A "Faster" lens means you can shoot at higher shutter speeds because you have a wider aperture range to play with (lets in more light onto the sensor) and avoid blurry shots from having to shoot at slower shutter speeds for properly exposed shots.
Quick rule of thumb for crop body (not using a flash) to avoid blurriness, the minimum shutter speed is 1.6 times the focal length used in the shot, so if your focal length is 50mm, your shutter speed should be 1/80 at the lowest. If you're using a longer focal length, like 200mm, your shutter speed should be 1/320 or higher (but if you aren't getting enough light at that shutter speed, the photo will be under-exposed, unless you make other adjustments).
Of course, if you have super-steady hands, you can try lower shutter speeds, but if you have people moving during the shot, you won't "freeze" the action at lower shutter speeds. Oh, but with IS (Image Stabilization), you might be able to get away with 2-3 "stops" down on the shutter speed selection, meaning if you needed 1/320 without IS, you might be able to shoot at 1/250 or 1/200 or even 1/160 and get acceptable results.
I really would encourage you to go to a camera store (or Best Buy) and check out the Nikon and Canon bodies you are considering, along with the long telephoto zoom lenses, and see if you think going from the 250mm lens to the 300mm lens is really worth the added costs for the longer reach.
Patrick, your post implies the only difference between the two lenses is 50mm of maximum focal length, which simply isn't true. The 70-300 is a higher quality lens. Do you really think the only difference between them is their zoom range?
Ron, yes, most community colleges have decent photography courses. I would avoid camera clubs, to be honest.
No, not arguing about the quality of the 70-300 over the 55-250, but the 70-300 is an EF (full frame) lens that will act 1.6x longer on a crop body for an effective range of 112-480mm, and it's also USM for faster and quieter auto-focus, while also being usable on the full-frame bodies as well.
The issue is cost/benefit for a beginner like Ron. Let's get Ron into the not-so-deep end of the dSRL pool, and see how he enjoys shooting with a dSLR, and see if he can justify a more expensive, faster and bulkier zoom lens later once he gets ready to swim in the deep end.
But if Ron decides he wants the 70-300mm lens, that's his call. If he thinks he'll be shooting a lot of far away objects and get his money's worth with a longer lens, then, that's what he should buy, but if he ends up using the wide lens 80%-90% of the time, then spending so much more on a long zoom lens feels like a waste of money.
Knowing then what I know now, I'd held off for a 7D, get the EF-S 17-55 F2.8 and the EF-S 70-200 F2.8 lenses, and skip the kit stuff. And that's probably $3500+ for just 3 main components. But I wasn't prepared for the initial outlay of cash at the time to make that big a jump on something I wasn't 100% sure I'd be happy to live with given the trade-off vs. toting a smaller compact digital camera with decent zoom range, but not so bulky in other areas.
What you said was "see if you think going from the 250mm lens to the 300mm lens is really worth the added costs for the longer reach." as well as "so the difference between the reach of 250mm and 300mm isn't much, but the cost is more than 2-folds, but not 2 times the reach or benefit, IMHO." You never once even alluded to the difference in quality between the lenses. The fact is, most of the better lenses will be full frame. That's reality.
That sounds intentionally designed to confuse a person who is unclear of what he is dealing with to begin with. No wonder this is such a difficult decision.
One other thing. I would never encourage someone to go to a store to check out equipment they have no intention to buy from that store. All the equipment being considered is well designed and will function just fine. Ron will adapt to whatever his choice is. Don't waste the time and resources of a business for your own gain.
FWIW, I don't think I would want to buy a lens that I have absolutely no intention of keeping.
Since a big reason Ron is going for a DSLR right now is for better tele performance, it probably doesn't make too much sense to err on the side of skimping on the tele lens (at least when the lens in question will still cost less than the body itself). IMHO, the only way it'd make all that much sense is if Ron does plan on keeping the lens even if he upgrades later (say to one of the hefty L teles like the 70-200 f/4L IS or the 70-200 f/2.8L IS). Although I'm not exactly averse to selling stuff, I do wonder about the used market for an inexpensive kit lens that's limited to 1.6x crop factor -- it probably isn't good after the first year or so though I could be wrong...
Then let me say this: I don't think the 70-300 represents twice the quality or usability over a 55-250 at twice the cost. You may disagree, that's your opinion. Yes, it's got a longer reach, quicker focus with USM, but relatively same low-light focus capabilities (i.e. it'll hunt in low light). It might get Ron marginally better looking photos, again, that's a guess on either side of the fence. If Ron is going to use a zoom lens at least 50% of the time, sure, he should spend more, but why go half-way with a relatively slow zoom lens, just spend some more and get the faster lens at the get-go. Plus, Ron was considering the crop-body models, and the EF lenses are solid lenses, but perhaps overpriced for his use on a crop-body and intended use in the short/long run. If I was considering EF lenses, I would stick with the L series, and not bother with the non-L series lenses, but at F4 for most L lenses, they are probably too slow at this moment in time, though IS is helping with 2-4 stop shutter speed advantages (but the IS for the L lenses will exact even more of a higher price over their non-IS counterparts).
I anguished over buying the EF-S 17-55mm F2.8 IS USM lens that cost almost 9 times the kit lens (18-55mm F3.5-5.6 IS), but in the end, I wanted a lens that did what I wanted it to do and could capture what I needed capturing in lower light situations, and the kit lens just wasn't doing it for me. But I couldn't make the decision until I had time to figure out the limitation of the kit lens.
I've stared at plenty of TVs in stores that I had no intention of buying at that store, and I've asked those TV salesmen questions if I had them. That's part of their job. It's part of the cost of being a retail outlet. Sure, it sucks for retail stores that some people will simply check out the goods at a retail store, and order online, but what if someone finds that a retail store will match an online price, and provide financing as well? It never hurts to ask when you are considering the look-n-feel of camera equipment. Some models fit people better than others in terms of the ergonomics. Some cameras just feel odd, while other models will feel better, and be laid out better when it comes to buttons, switches, etc.
Patrick, you've cornered yourself and I realize you will continue to argue in any way you can to defend it. If the arguments you are presenting now were truly valid, you would have used them to begin with rather than using the half truths you actually chose. I also recognize you intend to give assistance, I just think you are doing a bad job of it. There is no way on earth Ron will buy something like a 2.8L (which is what, more than double the price of the camera?) at this time, and I'm not at all convinced he would be happy with it if he did. It's a lot of weight to carry around. It is quite likely he will be perfectly happy with the 70-300 for many years, probably not the case with the 55-200.
BTW, I've decided I'm just not going to discuss the decision anymore, regardless of what anyone else says. Either of the options Ron is considering is perfectly fine and I'm fairly certain he will be happy and can continue on learning more about photography. When I try to counter contrary advice, I just come off as mean.
Ron, in spite of that, you are more than welcome to ask more questions. I'm just not going to try to counteract anyone else's advice.
Ron, I'll let Sam answer about the camera body because I have no idea the specific differences. In any situation, I would take the 18-55 that has been offered. I wouldn't get the 18-105.