Processor. You have a GeForce already and it's no use buying EVERY generation of graphic card that comes around! ( ie, wait until the NV20 before thinking about that) You CPU tho is what you could work on. Are you an Intel loyalist? If so, go for an Asus CUSL2 mobo and a 866 PIII or something like that. If you do not care about brand and want performance, go for a Asus A7V with a 1Ghz athlon tb. ( hey, it's always cool to call you friends and ask them if they want to drool in front of your 1ghz pc...
Can't really agree with you there, peeps. If you have read a few benchmarks on video cards, you can't have avoided to see that the only way to improve gaming performnce these days is too buy a better video card. At least if you want to play at 32-but 1024 and above. Like Anandtech said when testing the P4: "At 1024 x 768 x 32, once again, we're limited by the memory bandwidth of our test GeForce2 GTS. This illustrates both the need for a more efficient memory subsystem when it comes to today's graphics cards, and it also illustrates that you don't need to have a 1.5GHz processor to run at these high resolutions, a 500 - 600MHz processor will do the job almost as well."
Get a TBird 1 Gig which cost about the same as PIII866, make sure have some good cooling and you will be a happy man. I have a PIII866 on CULS2 and a TBird 1Gig, the TBird alot faster machine. Setup wise, the PIII866 + CUSL2 give me lots of problem as compare to TBird + A7V ( no problem at all from setting up the hardware to software installation + 100% Stable ). Pay some attention for the the cooling part you will be fine.
All the while i was using Intel CPU (from 8088, 286... PIII667 to PIII866, until recently i bought a Tbird 1Gig. Frankly speaking i get the most satisfaction out of this Tbird as for its price and performance.
As loyal as I am to AMD you are being misled, Obviosly cost is a factor or you would buy both correct? To upgrade to an AMD Tbird would also require a new motherboard thus making this not a very cost effective solution at all. You did leave out a bit of information as to the make of your motherboard ( can you run 133 mhz bus?) but the processor solution is the most cost effective I reccomend trying out the p3-750 which is still more than enough for todays games.