Forced with an OS reinstall after my wife's computer died (Windows XP doesn't like the motherboard being swapped out from under it), I started her with Ubuntu this weekend.
With XP she was already using Firefox and OO.org and she's been using Gimp for awhile, so that wasn't a hurdle. She migrated to Gmail/Google Calendar a long time ago, so there was no need to learn how to use an Outlook replacement. It didn't seem to take her much time at all to pick up the file manager, and the "Places" menu allows her to jump around quickly without necessarily knowing how a Unix filesystem is structured. She seemed appreciative of the games included in Gnome (Mahjonng, Minesweeper, Solitare) , Hearts was easy to install, and we had one small Windows game that worked just fine in Wine. Using SD cards from her camera is actually easier due to the fact that it shows up under Places with a recognisable name and has an easier to access unmount function. She was using an older version of AIM for IM, but seems comfortable with Pidgin.
At some point I'm going to have to tackle a VirtualBox install so we can use iTunes to sync her iPod touch (Fuck you very much for locking the music database, Apple). I already have an XP image available on my system that I should be able to easily copy over.
Overall, it seems to be going pretty well. Except for a problem caused by the maliciousness of one device manufacturer (fuck you again, Apple), all hardware worked painlessly (I was surprised to find that even her printer was automatically installed).