well I'm running an 8500 OEM........and my experience hasn't been that great. I know that every time someone brings up the issue of ATI's drivers it divides people into those who A: think ATI's drivers are just fine, and think anyone who says ATI's drivers suck are just anti-ATI and B: those who have problems with them.
Personally, I'm in the B section. I've had my machine crash, and i get the XP message saying the crash is related to my ATI drivers. I get random lockups in ALL my FPS games, ghost recon, CS, DOD, UT, Tribes2...and some seem to be loop-type lockups, and others seem to be an overheating issue or something. (although i've read up on creative's SB soundcard issues causing crashes and this may be contributing to it).
As far as graphics quality, the graphics are good, the 2d is excellent except for the "font corruption" issue that some people are coming across....Sometimes the fonts onscreen just won't show up with all the pixels in individual letters, (usually what happens is most of the vertical lines in letters disappear).
I have to say that I am going to run a radeon 7000 in a secondary machine that i'm going to build here in a week or two...i'm ready to give ATI another try but I will have to say that my Nvidia gf2 never gave me the problems i've encountered with ATI so far.... and there was a thread here at OC about the font corruption, so i'm not the only one who has experienced it.
anyways.....my personal opinion is that buying ATI is kind of a crap shoot....for some people their cards work just great and other people have constant problems with them. I'm about to RMA the 8500, so I can sell it and give the gf4 ti4200 a try when it comes out....the prices will be about the same, and we'll see how the nvidia product does.
oh...here's an example of the "font corruption" problem I've encountered: