Yeah, it's pretty hard to find gifts for me. Most of my favorite gifts are things I picked out and people paid me back for, like others mentioned. Money is awesome too. I don't care how impersonal it is... I love it just as much.
But I can think of two gifts that were a surprise and that I really loved. One was a computer tablet from my INTP ex. It was especially meaningful because it was roughly 6 months after we broke up and he was making up for all the gifts he couldn't afford to get me when we were broke college students

. The other was when my ESTJ boyfriend at the time got me a plane ticket to go see him in NYC on my birthday. My appendix had other plans though, and decided to put me in the E.R..... so he got the ticket reversed and came to see me instead.
So bottom line: We like your time and meaningful acts more than the actual item (even though that tablet is pretty sweet). Also, maybe nice things we wouldn't really buy for ourselves. Someone once gave me a nice coat I liked, and it would have been forever before I bought one for myself. Oh, and trips. Trips are awesome. If you can afford to give that kinda thing.

Gift certificates to stores we like are always fail proof.
Edit: Oh, and really practical, useful things are awesome too. Someone once gave me a thin wallet I could put in my back pocket. I never use a purse. So before that, all my money would be in wads and I would occasionally lose cards that fell out. Lol.