Ok. Well, if your looking to go SLi in the future, your choice will hafta be a 680i or a 650i chpset. But if your on a budget......the 680i run $229-$400. Im running the Asus P5N32-E SLI
and i really like it. It has great overclocking options, and has been very stable for me. Some people say its picky about memory, just check the compatibility list before buying RAM.
Otherwise you can grab any of the reference boards. The 650i is cheaper, closer to $150 if your on a budget.
Edit: On newegg right now u can get $50 off a ASUS 8800gts with the purchase of the P5N32-E SLI. Not a bad deal!