G.♣.
I love my Nook Color. We paid $200 for it last Christmas, and that's what the Nook HD costs. I'm sure a Nook HD would have more to offer, but I haven't actually looked into it.
Do you know what she wants to use it for?
ETA - I also chose Nook because I like being able to walk into a Barnes and Noble and ask questions. Great customer service so far! They also have classes in the cafe. (just look at their website) Very informal. The day I went there was the instructor and two other people. We just sat at a table with our Nooks. She showed as a few things while we played around and asked questions. It was very helpful!