I'm actually starting to get a little pissed off at one of my 07 machines. The x1900 is constantly overheating and locking up the system. Granted this happens more on things unrelated to Catalyst but nevertheless.

Sadly though Apple's "Geniuses" didn't do anything to help when I brought it in to be looked at.

I lost the machine in the middle of a show and was freaking pissed because the only way to fix it was to invert the compressed air after a reboot. Just fair warning, it's always good to have a hot spare machine onsite and a tech that can swap them for you.