If I were you, I wouldn't buy the 8800GTX yet. Besides the fact that the prices are insanely high ($650 - being sold for $50 over MSRP), ATI hasn't even come out with their DirectX 10 card yet as competition, the R600, which from the looks of things, is going to own the G80.
Besides that, right now, it's really impractical to buy one since DirectX 10 isn't even out yet for the public and no games are going to use DX10 for a few more months, and by the time they are available, the price will have dropped.
I'd really recommend a Core 2 Duo, face the facts man, even though I love AMD, the Core 2 Duos simply own all the AMD chips right now. I'd recommend an E6600 for Intel, or if you NEED AMD, get the FX-62 with that insane budget.
Buy an E6600/FX-62 now, and wait a bit for the Radeon R600 to come out. See how the benchmarks and prices compare, and then buy one. If you've already got 2 8800GTXs, just slap one of them in the new PC while you wait for the R600 release. No current games really need the power of 2 of those beasts anyway.
C2D E6600 | 4GB DDR2-800 | 9800GTX+ | Asus P5B-E | 150GB Raptor | 320GB 7200.10 | 750W Xigmatek PSU