You have quite a few choices with this sort of budget. If you're looking for an AMD system (and I assume you are given you've stated gaming as one of your key priorities), the
DFI LANPARTY nF4 SLI-DR is quite good, as is the
Asus A8N-SLI Premium. The
Asus A8N32-SLI Deluxe is great as well, if slightly overbudget, due to it's full SLI x16 support.
If you don't intend to use SLI, something like the
Asus A8N-E or
Asus A8R-MVP would be good options.
What sort of system do you intend to build around it (AMD or Intel)? What will be the budget for the entire system?