My Wife, who isn't particularly good or interested in computers, made the switch from Windows to Linux with only about 15 mins training from me,
My seven-year has no problem switching between windows and KDE, deopending which computr he is using, nor between MS Word or OpenOffice.org - I don't think he really notices. It's like being bi-lingual, sometimes he uses some words, sometimes he uses other ones depending where and who he is with.
Syd