When I installed Kubuntu 10.10 I encountered one glaring issue.
I am using the Nvidia 3rd party driver for my GTX 260 core 216 Evga video card.
The problem, an odd opaque box that extends through the left of the desktop.
In order to solve this issue I combed through the usual suspects at various web sites.
What I found was a great deal information that did not relate to the issue at all.
And a few tidbits in places that pointed to Desktop effects.
Ultimately, someone had suggested disabling desktop effects entirely.
When I disabled Desktop effects entirely, the problem went away.
Then I re-enabled the desktop effects and went through the options.
When I disabled V-Synch and changed the filtering to Tri-Linear as opposed to the default of bi-linear, the issue was resolved.
Start —> System Settings —> Desktop Effects —> Disable all Desktop effects