When someone asks what I want, I try to make it easy for them by saying a gift card to one of the following: Starbucks, Barnes and Noble, or local confectioners in my area. It's like a sigh of relief I see on their face/shoulders.
I don't do the "just having you spending time with me is enough," etc. Even though I don't need anything, I know if I personally asked someone what they would like to have, I would want an item I can go out and purchase or I wouldn't have asked them. And also, I fully realize that they would go out and try to find something anyway, so why not tell them up front what you want or could use?
My family is very good about giving me gift cards and I appreciate that. I don't have to return an item that didn't fit, wasn't my color, didn't like in any way, shape, or form, etc. Easy for them and exactly what I wanted and I am guaranteed to use! 
Same with my birthday.