I voted "other"- I'm a bit like Beck's response above. If there is something new or cool available, I'll add it. I don't add one just for the sake of adding, though.
My take on it is that adding a free gift isn't going to cost EF any extra shipping charges on your order, and they're already giving away so many free ones that an extra with your assignment isn't a big deal. If you're feeling a little guilt over all of the freebies, reviewing your free item should more than make up for it!