foolycooly and croc have good points.
Get vist home premium 64 bit. Needed for dx10, and 6gb.
Asus P6T is good.
A 1000 watt psu is overkill, unless you are planning on sli.
The GTX295 requires 46a on the 12v rails and 680 watts.
The corsair750w would do nicely.
Also, this build will not last forever. It will be dated a year from now. Still, it will run everything out there well.
But,... If you wait for the next best thing, you will wait forever.