Under $500?
An HTIB? Already have a DVD-Player?
Well...first thing that comes to my mind, hmmm, I'd say...
If you care more about pure audio quality and functionality than having a stylish system...
Onkyo HT-S770 6.1 (google search)
You honestly can't do much better with the budget price, about $400 new. Nearly half that used.
EDIT: oops, I forgot about the
HT-S780 7.1 (
google search) for just a few dollars more...