The volume of comments about issues in upgrading to 12.04 seems pretty scary.

Personally I would make sure all your data stays in the cloud (Dropbox, UbuntuOne, etc) and is backed up on external drives (cheap now) and CD/DVD if possible. and when you are ready to go to 12.xx, do a clean install, install your key programs again and resync the data back in.

If you have a fair sized disk one good option (that I actually did) was to partition off another 100GB and just put it on that and have that be the new default first item to boot (which it will normally be with this install process) (actually a pretty good way to get several consequitive Ubuntu versions out of 1 machine !!!