I'm a non technie & happy with my N9. I've even successfully downloaded & run some apps which are not from Ovi Store like Open Video Player, Opera Mobile, Firefox nightly, VLC Player. N9 has tutorial guides here, everythingn9.com & my nokia blog, it's not hard, just treat it like you would your PC.
Plus I dont have a N900, Maemo/Meego is new to me. Being a long time Nokia user helps though, as the contacts, calendar, messaging stuff are as per the usual Nokia format.

Dont worry about females 'not getting it', as long as your wife is computer literate, can do some simple troubleshooting, willing to explore, no problem.