I installed Debian Squeeze today, alongside my existing Ubuntu 11.04 installation. Since then, the "Hibernate" option disappeared from Ubuntu's Shut Down dialog and from the menu of the Shut Down panel app.
Any ideas?
During the Debian installation, I shrunk my Ubuntu ext4 partition and formatted the freed-up space to us as my Debian partition. Debian's GRUB was written to the master boot record (and choosing between Windows 7, Ubuntu and Debian works fine).