To me, you look most handsome in H and X. But I'm a straight guy, so take that with a grain of salt. I'd recommend P2 and X if you're looking for an "average 20-something" girl--the kind who goes clubbing and whatever. But if I were to see the equivalent kind of picture to P2 or S with a girl in it, I would be inclined to think that she's "too normal" for me, and wouldn't have anything to ask her about in the picture.
As someone said, there's no picture here where you're actually doing something that shows who you are. In picture H, I can make out a tent in the background--but if this were a girl, I'd prefer to see her next to a tent that is actually out in nature somewhere, with interesting scenery behind. I realize, though, that it's hard to take pictures like that. I myself am in big need of someone to go out on nature walks with me who knows the look I'm going for (the "nature dreamer boy" look) to take pictures of me showing that.