Just like it says on the tin, I just installed Catalyst 10.6, and now Quake II it's expansions, and Kingpin are crashing at startup. They were running just fine before.

there's no ATI analogue for nHancer?

I dunno if AtiTrayTools does the same sort of thing, I haven't used an ati card in a long time.

Well then why are you giving advice on an ATI card?

I didn't realise that is a prerequisite for keeping up on tech info or offering my help.

It's like a mac user giving out PC advice, though. Anyway, I installed ATITrayTools, and there aren't any "extension limit" settings.
[EDIT]
Cleaning out 10.6 and installing 10.4 again fixed it. I'll bet it has something to do with the fact that 10.5 an 10.6 were focused on video playback, though I don't know how that affects OpenGL games.

Someone on the forum of Steam found a .dll file which solved the problem for me for Kingpin (as well as Quake II, and the laggy gameplay and cutscenes in American McGee's Alice), try this link : http://www.filefront.com/16696483/atioglxx.rar/
and put the file where your .exe files are located.
It may work with other games based on the Quake 2 engine.
this is not useful if you use older drivers like 10.4, as previously said.

Hey, thanks for that file, it worked first time! :)
(although it's always running in windowed mode, even if I select Yes to fullscreen). No matter, working is better than not at all!

Thanks a bunch, Darucas, it fixed the problem for me too :)

Also, to reply to GamerGuides, I found that any resolution above 1024x768 made the game go into windowed mode. If you stay at 1024x768 and under, it stays in fullscreen.