I'm gaming on a socket 939 dual core AMD system right now, I've got a x1900xt and i'm all overclocked. I'd been considering rebuilding with Core 2 or AM2 but the start reality is - neither are worth the money.
Consider this - I'm gaming at 1600x1200 so where's my bottleneck? Yep, that's right - the GPU. So if I bought myself a 8800GTX instead of a new motherboard, memory and CPU i'd see a major speed boost versus next to none. This seems to be confirmed by looking a my ikkle cpu/temp monitor (parallel port driven 2 line LCD) which _never_ shows the cpu maxing in-game, especially when that game is graphically intensive. With multi-core aware game engines on the way I'm starting to wonder just how long it is till i need to replace the core system components - my guess is not until quad core is commonplace/affordable.
Do you disagree?
My only problem is that I'm not sure how long the 8800GTX is and since a 1900XT only just fits in my case... Dremel time for a new card? lol.