The best CPU would either be a intel core i7 920 or an overclocked E8400. This is because the new core i7 920's are much faster because of the newer architecture despite the outer appearance and the lower clock speed. But it wont be cheap be ready to be looking at a 1500$ computer alltogether for all of the correct parts. Thats the cheapest i got mine down to before shiping and everything else. The best bet would be to wait for a month since this i7 is such new technology and then all the chip prices will drop and be a little less expensive.