If you want something stable that doesn't change much from one release to the next, you could just not upgrade. Ubuntu LTS releases are supported for 5 years, and that support includes backporting hardware-enablement work.
My mother started off on 8.04 LTS. When upgrading to 10.04 LTS the window buttons changed sides and there was a new theme (this is enough to throw many users). When upgrading to 12.04 LTS there was a change from Gnome to Unity.
My mother now chooses to use a Mac because she was fed up with her computer "changing" each time I updated it. I doubt I could convince her to try any Linux distribution again - there are no perceivable benefits for her.