I think that you'll be happy with the A64. I went from a XP 2100+ @ 2367mhz as my main rig to my A64 3000+ @ 2420 and I am very pleased. It feels faster in most apps and most games run smoother compared to my XP. The A64's do overclock pretty well, mine will do up to 2520 (280x9)@ 1.68v (not games stable though), I just need some more volts if I want more. Still, that is a 20-25% OC friends which is not to shabby. You just need a motherboard that will allow a good overclock which leaves most current VIA based boards out.
The a64 3200+ is a little faster in most everything compared to the 3000+ at the same clock speed. The extra cache is usually good for an extra 3% in games and benchmarks.
