I'd be leery of buying one of the lower grade video cards. Oftentimes the previous generations top card (x1950 xt) will cost less or about the same as the lower grade new card while trouncing it in performance. Be sure to check the Tom's Hardware video card comparison chart and do a couple hours worth of research before buying anything:
http://www23.tomshardware.com/graphics.html
It looks like the x1950 Pro (not even the XT) beats out the 2600 XT right now. Newegg currently has one for about $130 shipped after a $40 rebate. (It's the HIS card, but be sure to read the negative reviews before buying.)
Now is a very yucky time to buy a video card, btw. ATI isn't very competitive and there aren't too many good options in the $150-200 price range. (Only thing to buy in that range is either an x1950 XT or a 7900 GTX, if you can find one that's reasonably priced.) Supposedly, a new line of nVidia cards is due out in a couple months using the new G92 core, which should put some downward pressure on the 8800 GTS.