One of the first things I did was download MAMEUI64
I was floored.
It runs just about everything full speed - Cruisin, Carnevil, NFL Blitz 2000, - all those games that I consigned to my custom-made "Technical Fail" folder (the "Fail" folder is different, it's for those games that genuinely suck) in the past.
Tekken 3 and Beatmania - just wow.
My new system is:
Windows 7 64 bit Intel i5 2.80 ghz x4 Corsair Ram 8gb 120GB Corsair solid state drive 1TB normal drive (with MAME on it) ATI 5760 graphics