That's pretty close to mine... i have two gigs cause i heard the x2 will be shorted unless you do. Make sure that you spend the measily 30 dollars or w/e to get low latancy ram; it REALLY speeds up your system.
also, for the graphic card i might recommend the leadtek 6800gt; its under 300 and is a great oc'er, my friend has one at 450/1150 i think!! Thats about what a 7800gt does and it stays well under 70 degrees too!!
if your building an SLI system, make sure to get a complient psu, gc, and mobo (i see you have an sli mobo).
Personal preference here: buy a sound card, whether the x-fi or audigy 2 zs, it helps with games a LOT.
It all looks like a great set-up though
