with the recent cards by nvidia and ATI, the ATI cards are far better both in terms of performance, quality, and price. for a nice and powerful card, the radeon 9800 pro/XT are great. i have an ATI radeon 9600 PRO...great card, wasnt too expensive when i got it ($250 CDN). i also have a 9600se by HIS. only cost me $125 CDN and i havent found any games that run better on my pro than the se
so it all depends on your budget. for high-end range, go for a radeon 9800 XT, for mid range, the 9600XT, and for even less money, the 9600se is incredible. i think u get HL2 free when it comes out if you buy a 9600/9800XT...
dont buy anything cheaper. i also have a radeon 9200, Geforce2MX400, and Geforce4MX440. all three of those are very shitty. thank god i got most of those free.....