No question. 8800 GTS. DirectX10 capable. Will play any game on maximum settings. My friend has a similar setup and he bought the 8800 GTS recently. He loves it. Since I am stuck with the X1900GT, I have to go through the pain of listening to him hit 100 FPS on max settings in this game and that...
Or you could pay $180 (including shipping) for a E6600 on eBay and wait two weeks for it to ship.
If I were making a decision, I would wait till Crysis comes out and base my purchases on what will play that game on DX10 effortlessly (or in medium quality). At the moment, I am saving up money...
First, could you provide the specifications of your system? Second, I agree with you. I wouldn't update my system right now. I would wait later on so you can upgrade to a DX10 capable card.