I'll post my results should I change my mind and succeed in upgrading, tho it rather looks like a reinstall at the moment which I have about as much a head for as for a nazi row. (I haven't reinstalled since 2003 and I'm not willing to start now.)
You will find that installing the *buntus of today is much easier than any distro was in 2003. In fact, I don't "upgrade" [K]ubuntu installs, rather I fresh install and restore /home. It takes about half an hour and there is no danger of some wayward or forgotten PPA messing things up. I do keep track of which programs were installed though, and a quick apt-get installs them all on the new system as well.
Sometimes a user's config file will be incompatible with the newer version of the software, but that is very rare. In fact, in recent memory the only time I saw that was KDE 4.1 to KDE 4.2 had a plasma panel config problem. It was no big deal.