I suggest a pair of Def Tech Studio Monitor 55 speakers for your main speakers. They are excellent and run $300 each. The Pro Center 2000 will run $349 to go with them, and a pair of Pro Monitor 800s will finish it off for $120 each or so. Those are list prices and I am sure you can find them cheaper if you do some looking around.
For a subwoofer, the NHT B12D is excellent, for around $700, and the Klipsch RW12D is pretty good for $400...etc.