You are really only going to have a problem with 3d games. Any 2d game should play perfectly (well, as perfectly as the emulation anyway).
I'm running similar processors in both my setups, so here's my $.02
I'm running a 2.9Ghz X3 on my main setup and can run anything but the known processor hogs (blitz, gauntlet legends, san fransisco rush)
It replaced a 2.8Ghz X2 and that ran everything just as well. Tekken 3/Tag may have less sound skips now.
I used the 2.8Ghz X2 in my driving cab for a while before replacing it with a 3.2Ghz X2.
Cruisin' USA and Cruisin' World ran perfectly fine on it.
I don't use the computers for anything else and have all unnecessary background services turned off.
You should be fine with that processor.
AS far as Blitz goes....
My hard drive died a couple weeks ago, so I experimented with XP64 while waiting for a warranty replacement.
Blitz went from freezing up to bouncing between 85-100%. Not perfect, but playable.
I played a full four quarters and had no issues aside from the sound stutters and occasional slowdown.
Sure those are issues, but with XP 32, it would just freeze up after you picked your teams and that was it.
It felt kinda nice to play a game of Blitz on a $250 computer after all the discussions of the high specs needed.

California Speed went from running at 85% to a solid 100%. I was amazed at how much of a difference it made.
Nice to know, but I restored my old backup image which is only the 32 bit XP.
I'm waiting for the 64bit version of Demul .5.6 to come out before I redo everything.
(Driving and shooting games weren't supported in previous versions)
Not sure how well other emulators work with it, but if your main focus is MAME, definitely start out with a 64bit OS.