[xendula]

If you get the basic kindle, make sure you get the black one. It has better contrast and a more pleasant background than the silver.

I would recommend either the basic or the Paperwhite. WIth the basic, you still have a bit of a learning curve, since there is more than one button. My non techie sister got used to it, but I think the PW will be much easier for her to operate. Also, you can see the covers on the home screen of the PW, so it may make it more appealing if you try to get her into reading.
If you get the 3G version, shopping for books would be easy even for a very old nontechie person - assuming she does not have a wifi network or computer set up. Shopping is extremely intuitive on it, even though that was not one of your requirements - just letting you know.

I never wanted a touch device, and now that I have been using the PW, my poor basic kindles are collecting dust.

You may want to go to Best Buy or Staples and play around with them both. I know, I am totally stating the obvious here!