Harbor Freight is a great place for throw-away tools, i.e. a tool for one particular project that won't get much use for anything else. For a decent inexpensive table saw I would check out some of the Delta, Rigid, and Craftsman stuff in the sub-$200 range. I'm personally a big craftsman fan and think they offer the best homeowner grade tools for extremely reasonable prices.
If you're going to be building speakers then you're going to be cutting circular holes. This would call for a router, spiral-cut tool, or jigsaw (in that order of preference). I think it's easier to cut circles w/ a spiral-cut tool (i.e. rotozip) but they're not as useful for other aspects of speaker building (flush cuts, rabbit cuts, round-overs).
If just want to build some speakers and nothing else then the stuff from harbour freight (probably Chicago brand) will probably do you fine. If you're looking for solid quality homeowner tools (anything you'll need to do around the house, but probably not what you'd want to build a house with) then I would invest in Craftsman tools.
how many cuts are you thinking about? if you only have one project and you're friendly with your home depot or lowes guys they can cut them 'almost' to size. they may be off by 1/8", but it will be straight so that's easy to deal with.
if you plan on multiple projects (like a full 7.1 speaker system). I'd think hard about buying a table saw. the Ryobi BT3100 is very popular as a budget saw, they run about $300. you can read more about it at bt3central.com
don't go too cheap, nothing more frustrating then tools that don't work correctly...
Well, there are several ways you can go about this. If you truely only need to do a small amount of things, and you're looking at using only sheet goods (for example, MDF), you can really get by with a good circular saw and a clamp on straight edge. You can get an outstanding circular saw for $150 or less. I would get a direct drive (not worm drive) for this type of application, as they are lighter and easier to manage. Also, there are some manufacturers that make left blade saws that are much easier for right handed people to use. I have a Porter Cable that is very nice. There are different brands of clamp on straight edges out there, and there are even good DIY straight edges that you can make.
If you approach this setup by making youself some good sawhorses (to set your sheet goods on), get yourself a good 3/4" 4x8 sheet of plywood to set on the sawhorses, a 4x8 sheet of 3/4" foamboard to set on top of the plywood, and then set your MDF on top of the foam board. Clamp your straight edge onto the MDF, and setup your Circular Saw (CS) so that the depth of cut is about 1/4" deeper than the MDF. It will cut into the foam board, but not through it, and also will not get to the saw horses beneath it. This will give you a large table to work on, and lots of control. I would also suggest that you invest in a good true square, not the cheap junk that they sell at the hardware store. A good cheap alternative are the plastic laser cut squares and triangles that they sell in the drafting sections at Office Depot or Office Max, etc.
As for a good router. If you can only have ONE router, I would highly recommend finding a good deal on a DeWalt DW621 plunge router. You can find good deals on these on Ebay, and if you have a local DeWalt service center, they sometimes have refurbished units for a good deal. You'll need a good spiral upcut bit (1/4"). If you have a shopvac, I would highly recommend you use it with this router. It has excellent dust collection, and you'll thank yourself for it.
If you want to get into a table saw, I would recommend staying with a good contractor's saw. Grizzly's new G0444Z is a great deal on a fantastic contractor's saw. The Ryobi BT3100 have a huge fan base, but in reality they aren't a very wise choice. They do not have mitre slots, and they are direct drive units (very very loud). They are nice little saws, but if you're going to spend $300, then jumping up to a Grizzly or Delta or Jet would be a much better idea. A G0444 is $435 ($135 more), but this is a true contractor's saw, with a good fence (beisemeyer clone), etc. Really it depends on what you want to spend and what you need to spend. If you plan on doing more with a saw later, then a table saw is a good plan. The downside is they take up a lot more room to store it than a circular saw and straight-edge guide.
Forgot also that you had asked about the Harbor Freight table saw. If you are talking about this saw, then it is a decent little saw. It is on sale for $299 right now. I would say that from what I've read, the weak points are the motor (which tends to burn up in about 1 year's time), and the fence. For $135 more, the Grizzly I aluded to above is a much better choice, if you can swing the price difference. Much better motor, fence, etc.
When it comes to table saws, here are the important factors that you should be aware of, and not necessarily in this order:
** Align blade parallel to the mitre slots ** Align fence parallel to the mitre slots ** Have the right type of blade, and a good quality blade
Other than that, you want a good heavy duty build quality, good reliable motor, and everything else you can work with.
You can tweak a good belt drive saw by using link belts, you can build jigs to use, etc.
If you want some online vendors to look at, let me know and I can provide you with some links. Also, if we knew what your budget could handle, it would help to not point you in certain directions. I'm fairly certain you aren't in the market for an Altendorf saw or the likes.
In addition to all the good advice given so far, you might want to also invest $20 to $30 in a rolling device to "catch" the wood that you've passed through the saw, so the wood doesn't fall onto the ground. I've seen this device by Rigid at Home Depot for the price range I've indicated above. In saved wood, it would more than pay for itself since MDF is quite heavy and a bit hard to control at times.
I've built speakers with just a circular saw and straight edge, but if you want any kind of accurate edges for veneer, or anything, I found it to really be frustrating, so I bought a table saw.
I own a Ryobi BT3100, and think it's a great saw for the money. As far as it being loud, I would hope you would wear ear protection with any tool, so it doesn't really matter to me.
I have added miter slots to my BT3100, and what many people don't know is that it comes *stock* with a sliding miter table, which will add lots of $$ to any other saw.
Anyway, I've been pleased with my saw- I got it at Home Depot with a 10% off coupon for around $250 or so, I think. It has a 3 year warranty, and I can get accurate and square cuts to a couple thousands (checked with a digital caliper).
I had a cheap Sears saw, and the fence was misaligned to the blade, with no way to adjust either. A cheap table saw can be more trouble than it's worth. I built a pair of speakers and 2 subs with a circular saw and a straight edge. With this set up, the cuts can be as good as a good table saw, but will only be good if you take some time and make sure each cut is set up right.
Now, with a good table saw, I can knock out a set of perfect flats in 15 minutes. With a cheap saw, it took an hour and they weren't perfect. With a circular saw, it may take all afternoon, but I could get perfect cuts.
If you plan on doing just a little, get a circular saw and a straightedge. You may waste a lot of MDF learning, but MDF is cheaper than a good saw.
If you are planning on doing a lot, get the best table saw you can afford.
It also might pay to call a few local cabinet shops and see if they will make the cuts for you.
I had the ~$200 Delta table saw and was absolutely UNsatisfied with the fence. There was so much play in the movement that you could lock it down at the same spot on the front rail, but on the back edge you might be 1/4 inch or more from the previous lock down. Of course you'd have to be fairly oblivious to be off by that much but even when I was extra careful to try to hold the fence flush against the front rail as I locked it down, I often found that it still didn't end up parallel to the blade.
My temporary solution was to measure the "squareness" EVERY TIME. YUCK!!!! My permanent solution was to sell it cheap to a coworker. And yes, I did explain and even emphasize its weaknesses before the sale was completed. I haven't had a real need for a table saw since then. But I haven't done any speaker building since then and I've got a miter saw and circular saw to get me by.
For my next table saw I'll look for a fence that locks down at the same angle EVERY time. Preferrably a 90 degree angle
I have a ryobi BT20 table saw, and for 200 bucks, I'm damn happy with it. It's a folding base unit, so you can knock it down quickly and put it next to a wall in the garage. I've never used a "real" table saw since a good delta contractor saw that will last forever will set you back about $800 bucks, but this cheap thing makes accurate cuts, has a pretty good fence, and will treat you right if you treat it right. Spend a few hours at first getting everything aligned, and check your angles at the beginning of each session and you'll get perfect cuts.
It has a 27" right rip capacity so it can cut panels wide enough for any sane sized sub. The miter gauge is crap, but any woodworker worth his salt should build a miter sled and never use the thing. I've built an EBS shiva and a bunch of furniture with this thing, and I can't see myself shelling out for the delta for quite some time because the ryobi does everything I ask of it well. Just don't expect it to crosscut 8/4 hickory all that well...
oh yeah, and don't skimp on the blades either. It's not that big a deal when cutting MDF, but it you ever cut real (and expensive) hardwoods, get a nice 40 tooth Freud ATB Diablo blade, don't use the one that came with the saw or some cheap Oldham either.