ADDITIONAL COMMENTS: This is my first build from scratch, and I feel like I'm overlooking a few things, or perhaps not getting the most for my dollar. I'm going to be using this system primarily for gaming and want the freedom to upgrade parts as necessary.
With DX11 games starting to be released, I dont think the GTX275 is a good buy. Unless you are assuming you will replace it in 2 years for a DX11 card, I would go with a HD 5850 or even 5870 (which you could eventually run 3 of with that motherboard and PSU).
Oh and someone in another thread mentioned a few days back about how microcenter is selling the I7 920 for $200, here is the link. Should be quite a nice deal if you live near one. (no clue how they found it on there, as I can only find it through the link, no clue why)
Honestly, replace the 920 with a i5 750 and use the remaining money for a 5850/5870. Don't forget to change the mobo and memory as well. For gaming alone, you should be putting most of your money in buying the best GPU, which at the moment is the 5850 for less than $300