I used to have problems with a mobility Radeon on my Thinkpad T40 a couple of years ago but things may have changed
I currently have Ubuntu Hardy on a Thinkpad T60 with an ATI x1300. compiz ran out of the box. Have not had issues so far.
If I were a grave-digger or even a hangman, there are some people I could work for with a great deal of enjoyment. -- Douglas Jerrold