People should stop fanboyism tbh... I've had my fair share of problems with ATI and Nvidia Drivers...
the problem I faced with ATI with my HD 4850
couldn't do dual monitor setup without crashing..
the fix for it was simple.. reinstall drivers and make sure the OC facility in CCC remains locked, otherwise it would simply crash when running 2 screens.
The problem I face with my 9800GX2 atm are:
a small amount of flickering grass in Crysis warhead.
when flashed in CSS, you can't see a thing at all till the flash effect is 100% gone, cause the image just keeps on flickering.
Tried reinstalling drivers, messing about with settings, disabling multi-GPU. Still the same problem.
Still haven't found the solution for it.
Anyways, just go for HD 4890 !! Its a good bang for the money

Don't listen to people who says ATI drivers are bad, they both have their fair share of problems. In my case, I had more problems with Nvidia cards... but that doesn't put me off Nvidia too much.. the problems I face are probably due to my card being a dual GPU card. What does put me off more is the ridiculous price when you can get an equivalent ATI card for less money, so more beer can be put in the fridge.