If you don't want to spend that much money, I'd pick up a now-cheaper Phenom II X4 940, 945 or 955 (DDR2 + 3.0 GHz + unlocked multiplier, DDR2 or 3 + 3.0 GHz + locked multiplier, DDR2 or 3 + 3.2 GHz + unlocked multiplier respectively), and then the appropriate memory kit and motherboard. Or the new 965 (3.4 GHz) if you wanna go all-out.