"the comment about two partitions doesn't make any sense at all."
Because you're an idiot. Bootcamp will require the creation of a second partition (and it'll do it for you) so you can install a second OS on the machine. C'mon man, I'm not even a Mac guy and I know this.
Her price range ($1,500 - $2,000) and level of technical aptitude (or lack thereof) makes her a perfect Apple candidate. This is my recommendation too.
If she ever just -has- to run Windows, make sure to get the 256GB SSD in it, so you've got room for two healthy sized partitions.
With RAM that fast and cheap, 640kB ought to be enough for anyone!
Whoops, I mean 6.40 x 10^7 kB. THAT ought to do it.
Mathematicians practice absolute freedom. -- Henry Adams