With the risk of making all the ATI lovers here jump on my back, I'll say that I prefer my ASUS v7700 Deluxe. It has everything you need from a videocard, plus some extra add-ons. It installs without a hitch, has great tweaking utilities, comes bundled with great software, and the DVD player application has one of the best interfaces I've seen.
Now, here's another reason, which is less obvious at first sight: the ASUS (as well as other Geforce-based cards) will let you use your own hardware DVD decoder for output, as well as it's VIVO. Thus, you have TWO choices for DVD/VCD/S-VCD/DivX playback.
With the ATI, you put pretty much all the eggs in the same basket, as far as DVD solutions go, plus you don't get region cracking and so on... Last but not least, in terms of raw power, the Geforce2 beats the Radeon.