So you need 5.1 speakers and sub? That's it?
If so, I'd probably look at Polk, Energy, Infinity and Paradigm brands. I'd first use their respective web sites to learn more about their products, then look @ Amazon for user feedback, and also AVS forum for more gory details on how they might compare. Energy Take Classics is probably the best priced entry level 5.1 speakers/sub system right now. For $399 it's hard to do better. I have a soft spot for the Paradigm Cinema 90 too (which would fit your budget), although I don't typically see them as much in the U.S. compared to other brands. (Actually, Energy & Paradigm both may be Canadian companies?)
The other one that peaked my interest is the Aperion Audio Intimus 4B. Really nice sound for the money, if you can actually find one inside your budget.
I have a large theatre room which I am looking to install a 5.1 sound system in. What is the best system (w/out receiver) that I can get for less than $800?