I wanted to offer some suggestions for those who don't know what to buy the ereader in your family. Maybe you'll want to buy one of these for yourself... I usually order accessories on ebay.
As an ereader, I was really happy when I found a stand for my ereader. This is particularly useful when I'm on lunch by myself or cooking supper.
A gift card for an online bookstore! Make sure you know which store to get the gift card for.
A waterproof case. I don't have one but it would be great when reading in the bath.
*Please note I'm not affiliated with any of the online stores linked.