It'd probably be something from Doctor Who, anime (esp. AoT or Fairy Tail), Supernatural, Sherlock, LOtR, or Harry Potter. They have changed everything for me, and I would love to give the creators/ authors huge, massive, warm bear hugs.
**are song lyrics lame and unorginal? because i'd also fancy a led zeppelin/ smiths/ cure/ david bowie lyric on my body.**
I think anti-possession tattoos are the bomb. I don't really believe in demons (except for cats. they hate me.) but they do look awesome, and I'd love to get one on my wrist or ribcage.
Still going with the SPN theme, I fricking love Castiel. He's this poor, helpless, terribly socially inept celestial being with puppy eyes and amazing hair and just ugh I don't know he's adorable and fluffy and shit. So I would probably get a black feather/ wings on my back.
In general, tattoos are beautiful to me, if done right. I'm really hoping to get one someday. Except my parents hate them. I wonder what they would think if I strutted up to their house at Thanksgiving 10 years from now, with a dorky British dude (or lady ;*) and a few tattoos here or there.