After I suspend and try to wake up my laptop it just automatically reboots every time. I had this problem in 11.04, but it happened occasionaly. Now I'm with 11.10 and it occurs every time.
It is a sony vaio FW350. It has an onboard Intel graphics.
I also have this other problem since 9.10: http://ubuntuforums.org/showthread.php?t=1448330 I guess they are related problems.