Also try
www.tomshardware.com and
www.anandtech.com
I for one bought the 9600Pro from ATI and will never look
back. That was done after about 3 weeks of research. If
the Pro is in your price range, go for it. Stay away from
PowerColour, that's all. Otherwise the Nvidia 5700 prices
similiar to the ATI 9600XT, with performance as well.
DirectX9 games performs better on the ATI cards. Plus on
the new ATI cards you get the HalfLife2 token. Don't even
think of the Nvidia 5600.
-----Original Message-----
There are plenty of comparison articles on this. Try the
Maximum PC web site, they are nuts about comparing video
boards for game use. Right now, the ATI Radeon 9800 Pro
is probably the best, if you have 400 bucks or so to spend
and a fast enough CPU to not be the bottleneck.