@Paul Crawford - server/desktop releases.
I know that the LTS periods for desktop and server do not match, but I fail to see the difference when it comes to the repositories. I have a 10.04 desktop build (although it is used more like a server, but I do directly log in to it relatively regularly) in my environment, and it is still getting many updates from the repository.
I know that there is a good chance that some packages will not be updated (in particular, Chrome and Firefox updates do not happen, or happen infrequently), but the kernel and the basic OS appear to be receiving patches.
So I have taken the attitude that my 10.04 system will remain at that level for the foreseeable future. I believe that I will get basic OS security patches as long as the server LTS release is maintained, and most of the user-access stuff is sufficiently stable that I'm not overly worried that I may not get updates. Same goes for my Asus EeePC 701, which is really too small (4GB internal SSD - not upgradeable) for anything later than 10.04.
For the record, I'm using 12.04 with cinnamon on my laptop, and I am getting by, although I really would like to re-instate the pre-unity elevator boxes on my terminal sessions. The pop-up up/down/drag slider button thingy just annoys me when it disappears.