My mom isn't very, well, good with computers so I put Ubuntu on hers, and she loves it. It's very easy to use, but it still has all the awesomeness of any other Linux.
I use it to run the Johnny Two Shoes file server, although, i'm not very good at linux so mostly it's pretty broken. It doesn't really do what I want it to do, simply because I haven't got time to fiddle for ages.