Choose from what? If you posted an image, I don't see it.
Just go with what you like, really. You're the one who's going to be wearing it. =P
EDIT: Oh, okay, you edited a poll in. Tryed to make me look like a goon? XP
I'd say the bottom green one, but like I said above, it depends on what you want and what feel you're going for. (The top one makes me think of water, the second rock, the third rust, and the fourth, a forest.) Match a stock image (if you're doing that kind of sig) with one that matches its respective mindset, and you could have a winner.