Actually it's kinda hard to say which chip is better, through all the benchmarks it shows that some thing the 2800 does better than the 3200 and visa-versa.. in areas of benchmarking also.. So it's really up to, probably just go for which ever one is cheaper, even if it's a buck cheaper hehe
This is a good mobo for the 2800 Abit KV8-MAX3 K8T800 Motherboard
For the 3200 I'd stick to the Asus a7n8x - deluxe or e-deluxe boards..