I've not really had any ATi cards until this system (X1900XT) so I don't know that much about the drivers, other than they seem a bit crap compared to my old nvidia drivers
When I first installed windows I used the OMEGA drivers with ATITool. I really got fed up with ATITool taking an age to startup and using my resources, so I thought I'd try the Catalyst ones (7.1). I put the driver only on without the control center and it seemed ok. As soon as I put the Catalyst Control Center on I started noticing loads of problems and also changes in the picture quality etc
I also noticed a bug where whenever I ran cs:source, suddenly specular lighting was enabled, despite having it disabled in my config
it seemed as if the CCC was enabling it for some reason. I found a option which seemed to fix the specular problem and also finally got the image quality back, but now certain aspects don't work. Mainly looking on the fps test thing on cs:s.
So I'm thinking of maybe putting the OMEGA drivers back on without ATITool or should I put the catalyst driver only on (no CCC crap) ??
Be interesting to see what the rest of you use and why etc