the driver problems are pretty much nonexistant anymore, since ATI has been able to make good money on the 8500 and higher series, they have been able to devote more money to correct driver designs.
since feb. this year, they have released 8 completely new driver sets appearing in the catalyst packages.
I found that most of the problems associated with ATI cards were when someone installed an ATI after owning an Nvidia product, the nvidia drivers were causing conflicts, and should have been uninstalled before the new card was even put in... common practice for those who read manufacturer instructions
but whatever you choose to purchase, FX5900 or 9800, its going to be PLENTY fast. HAVE FUN