Re: dlp projectors
Yes, I would definitely wait for the reasons Jason just stated.
How much have you planned with how your HT is going to look? Do you have certain dimensions in mind? Figure out your screen size? Know how far back you'll be sitting?
LCDs typically have more SDE than DLPs, but there are many factors that contribute to it in addition to the LCD panels, for instance the resolution of the projector, the distance you're going to be from the screen, and the screen size. And as Jason mentioned, there are ways that LCD projector manufacturers try to lessen the SDE.
When you're picking out projectors in whatever price range you set, don't limit yourself to a particular technology, there are plusses and minuses to all of them and it really depends on what you want out of your projector. Personally, I've always stuck to DLP because I prefer the look I get and I don't suffer from the Rainbow Effect either (something you might want to consider). I also use my projector for gaming and I didn't want to have to worry about refresh rates or any kind of lag. Some feel that LCDs provide a more film-like picture and DLP has more of a digital look.
Some factors to consider as you shop for a projector: ANSI contrast ratio, black levels, lamp life, number and types of video inputs, lumens (Will your room be totally light controlled? Will you have enough to light up your screen? Etc.), do you care about RBE, what will you be using the projector for (Just movies? Gaming? All your video needs?), warranty.
When you zero in on a model, ask a bunch of questions here and be sure to read as many reviews as you can find too. Find out if the model you're considering has any issues, like Optoma had a few years ago with one of their model's lamp failing very quickly, or the Samsung 710AE having start-up problems.
Try to demo some different models in person too to get a feel for what you like best.