First, when and if do you plan on going SLI?
If you think you'll be wating 1+ years before doing so, don't. It's guaranteed to be cheaper to upgrade the card to one that'll outperform SLI.
And in that case i'd recommend ASUS P5K-E Wifi. And G92 8800GTS 512mb is the same as 9800GTX but cheaper. Also make sure you have a quality PSU, preferably one that has a Single very powerful 12v rail.