I am using Ubuntu Oneiric and have kept fully up-to-date with updates. My GPU is a Radeon HD6970, for which I am using the open-source Radeon drivers. The only change I have made to the 'default environment' is forcing the GPU to use a low power profile, by adding 'echo "low" > /sys/class/drm/card0/device/power_profile' to /etc/rc.local .
Whenever I suspend the machine through Ubuntu's power/settings menu, it sleeps just fine. After waking up however, obvious graphical glitches are present. Windows move remarkably less smooth and content in the browser is unreadable, for example. Hitting Alt+F2 and entering 'unity --replace', although moving all windows to the upper-left corner, fixes this.
Now I am looking for a more elegant, or at least a more automatic way of getting the job done. On IRC I was told to either fix the driver problems or add the aforementioned command in a pm-utils script. I am not sure how to do the latter, let alone the former.