Think about getting a wireless internet setup. Then remind her that A) the iBook will get excellent reception, and B) most lower-end PC notebooks require an external card with that thing sticking out. The iBook is a sleek, one-piece solution that gets better wireless reception than just about any PC notebook around.
And you already know this, but make sure she has enough RAM from the start. Like, order the RAM and a screwdriver to install it ahead of time, so you can install it before she even boots up the iBook. Using it with 256 MB of RAM will turn her sour towards it.