I'd go the route Monkish suggested. Start with a decent base and build up. Go to accessories for less.com and get either the Denon 1312 or 1513 5.1 receiver. Then have Best Buy price match the Pioneer FS52 floorstanders. Sometimes tiger direct has them as low as 100ea, so you might watch for that if you arent in a rush. Get two of those and go from there. Add surrounds, center and a decent sub as your income allows. You'll appreciate the system more if you save up and buy decent equipment as your budget allows.
Your other option is to watch craigslist.. great deals on used equipmemt can be had there!