I'm mostly an AMD guy, mainly because I've never really been fond of dual-core anyway, and my AMD keeps me at 75FPS at the lowest in all the games that I play; if it is lower, it's because I have all the settings all the way up while running a (1) 7800GT: it's the video card holding me back from maxed settings. 75Hz is my monitor's maximum refresh rate, so anything beyond that is completely unnecessary. Sure, the Intel Core 2 Duos would get me tons and tons of FPS maybe and better benchmark scores, but I honestly couldn't care about that. Someone's always gonna have a better benchmark score unless I hit the lottery and buy a million dollar computer, then overclock it like mad. Maybe I'll sell my computer and get a dual-core computer once they actually start getting some good programs/games that use them, because by then there will be much better CPUs on the market, and everything else will be considered obsolete.
And as for NVIDIA/ATI, though I used to be an NVIDIA guy, now all I really want is best bang for the budget. I guess you could say that I'm more towards NVIDIA because I've got a 7800GT in my computer and am really pleased with it thus far, but I may upgrade soon whenever I get the money, if I get the money. And I don't really have a preference as to company, but I'll go with EVGA because that's what I have.