On ubuntu 8.10 (32-bit, catalyst 9.3) and ubuntu 9.04 post-beta (64-bit, catalyst pre-9.4) running

aticonfig --acpi-services=off

after "aticonfig --initial" really fixes the X-server crash.

I have tested the catalyst driver a bit under ubuntu 8.10 and my first impression is, that the performance has significantly improved over the "stock driver" shipping with ubuntu 8.10.

Thanks a lot for the hint shiftear!