Well, what are your preferences for processors? Intel will give you better bang for your buck, but if you can't splurge for it, there are a host of good AMD processors that will offer great performance. And will you be overclocking the CPU?
I'm thinking of a couple of options for you. One would be to get an AMD chip, probably an Athlon X2 5000+ Black Edition and pair that with an 8800GT. The other option is to get an Intel chip along with the new Nvidia 9600GT, which offers great performance at its price point.
Let us know on the processor and overclocking fronts and we'll be better able to help you.