Curiously, this wasn't at all a hard choice for me. I just never got around to setting it down.
Now, not the short-hop style of teleport, to go through walls and such--no, I want long-distance teleportation. Want to go somewhere? Poof, you're there. Wouldn't that make going to see friends a snap?
Of course, such an ability would also carry lucrative opportunities, both to earn money and to do good. If I could carry just a couple of kilograms with me when I 'ported, think of the benefits in, say, organ transportation for hospitals. Great talent for a courier job. Not to mention spy missions.
There's the usual host of criminal applications, but I can't imagine that I'd use any (except under special cases, see below). There'd be plenty of legitimate ways to make a good living. The closest I might come to "crime" would be the above-mentioned spying. Though I'm not sure I'd want to let the US gov't know about my power. On the one hand, I could help them lots. On the other, I don't trust them.
On the bright side, it's really hard to threaten someone who has global teleportation powers. "If you don't do this, we'll shoo--oh, frak, where'd she go this time?" On the down side, I wouldn't necessarily be able to protect my friends and relatives from being taken hostage. I don't know that I'd want to be in a position to get blackmailed, or be a target.
Really, though, I don't care about being a super-hero or a super-spy. I just want teleportation so I can go visit all my friends. I'd be happiest if we could get Niven's teleport booths running on street corners world-wide. That'd do me just fine.