An AMD X3 720 is the best bang for the buck, and it's enough CPU to power a couple mid-ranges GPUs for gaming.
The i7 build leaves less cash up front for GPUs, but is more expandable.
I could change up on that build and switch cases to the Antec 300, and the psu to the OCZ 550w and then with the money saved change the vid card to a gtx 275 or a 4890 for a nice little i7 single card set up.
Thanks for great responses. I had a couple possible builds I could've posted, but this gives me more of an idea of what I'm looking at. This is the first time I'll be building, so this is all a little scary. I appreciate the quick replies.