You might also consider whether or not you think you'll be a repeat offender or not, so to speak. I personally would advise against getting one on hands or feet areas, despite how hot and bothered it'll make RatBastid
Reason being, your skin tends to stretch there more as you grow older and is worn a lot by repeated use, so the tat gets distorted fairly easily - at least this is what I've heard. If you think you might get another, I'd consider the shoulder area - I rather like the idea of being to cover it up when necessary.
Depending on the size, you might also consider the forearm area. I would personally vote against the calf, unless you've already got a bunch of tats.