I definitely agree on the taking your time. I know it's tempting to jump in, but the easiest part is getting it done, the hard part is deciding. It is for life, unless you like scars, so get something that means something to you. What means a lot to you, and will always mean a lot to you?
In spite of the fact I drew mine myself and really like it, I'm not sure I would have got the same one at at 26 as I thought I wanted at 19. I'm not convinced I want another one, I like the fact I just have one, but I am tempted by a slightly geeky typographic one. 😱
It is addictive, but it really, really is worth thinking through very carefully first. The amount of cash you hand over is in no way proportional to the effect it will have on your body.