Yeah man, you HAVE to chill with the 680i. It is much better for OCing, the BIOS interface is like the best I have ever seen. I think you should be fine with the 8800, because as zer0cool said, the next GPU out will cost you a bundle.
As for the proc, the 2.33 C2D is nice, but you can just get the e6600 for a lil' bit more and OC it to like 3.7 on air with the 680i mobo.