Ubuntu 12.04 is the latest and long term support (LTS) Ubuntu release.
It works really great (although with some issues), and I use it for business purpose as well as on home laptop/netbook. Occasionally, I experience a problem with touchpad on my netbook. Namelly, touchpad stops responding and mouse cursor can't be moved on screen.
I'm not sure what causes the issue with touchpad freezing, but the solution that works in my case is very simple - disable and re-enable touchpad support.
1) Press Fn (function key) + F7 in order to disable frozen touchpad
Information that the touchpad is disabled will be displayed.
2) Press again Fn (function key) + F7 to re-enable the touchpad
Now you should be able to use the touchpad without any issue. If the touchpad freez again, replay mentioned steps.