for an extra 20 bucks here is an evolution in performance. HL2 is very playable, as is with everything else:
http://mainst.fatcow.com/cgi-bin/shop.pl?SID=1109543498.12553&page=product.html&product=365
Not that I base all my buying on futuremark, the difference between a score of 500 3d marks and 3500 3d marks is big.
My A64 @ 2500mhz and BFG 6800 manages a 10500 in 3dmark03.