Although the fglrx proprietary driver installs (not without troubles but installs!), I cannot run opengl games under wine. I mean any. I tried Half-Life and Half-Life 2 they both failed. Unlikely, absolutely same system with nvidia card and their proprietary drivers performs quite good.
I was using xorg-server 1.7.6, even tried with 1.6.5.
I also tried installing different versions of drivers, beginning from 10.4 which doesn't support the card at all ending with most recent 10.6 which was most recent about two weeks ago when I've been testing that.
I had no luck under ubuntu either. The driver installs but then Half-Life terminates at the same point, loading two last menu items then terminates with no error message. Again, works in ubuntu with nvidia card.
How is that good?
Well, I could possibly by wrong and my ATI card was possibly broken I didn't want to repair it, because I had many troubles with this stupid driver, I had enough of this mess. To make a last point: you do not want ATI graphics for linux. Really. While installing the proprietary drivers you may experience lots of opengl errors, though installer is made with GUI part.
Get nvidia card. They cost more, but installation of driver is simple and performance is great. I've tested three different nvidia cards in the past with linux on different computers and never had any troubles like ones I had with ATI.