I usually have a lot of difficulty thinking of good presents for my niece and nephew. They're middle class enough to get all of what they need and most of what they want, and don't seem to have a lot of desires for stuff just to have stuff.
It's actually a lovely combination, but tough for an aunt.
My niece has recently decided that she wants to go to a certain university. It's a fine school.
So I got her a t-shirt with the logo and name on it for her birthday. She found an excuse to put it on last evening (I got here after dinner and gave her her present after dinner). And this morning she had it on again when we went out.
I win at being an aunt!