I'm not going to give any really specific ideas, just more general stuff, 'cause I'm not really all that picky. Except that fantasy or horror would not my first choices.
I'd love to find a good sci-fi, space opera type of thing with a slight lean towards hard-SF, Cyberpunk, d20 Modern-ish (with or without Urban Arcana) or Shadowrun, Star Wars, or something with superheroes, all pretty much in that order. And then horror or fantasy. Hehe, really, I just want to play
in something where the game-part comes just teensy bit before the sex-part, but structured, statted, with real plot and story and a GM or three. The size of the game isn't important, just so long as the GM isn't overwhelmed and can manage a couple posts a day (I'm probably 2-3 posts most days myself, though sometimes more) for all the players involved.
All in all, the system isn't all that important as I can get my hands on several different core rules for even older games easy enough. If I can't borrow it, I'm sure I can find a scan on eMule even if it's out of print.
For the adult part of the game, things I like: bondage and domination can both be pretty heavy, with the S&M kept a bit lighter (flogging and clips are good, blades and needles not so much), rape, public use, groups, male or female consensual (so long as it's not totally vanilla), monsters, tentacles, bestiality, humiliation, clothing is a big fetish for me too, along with my character losing it in interesting and inappropriate ways
I don't know which 'heavy' all that puts me into, but probably exotic, huh?
Stuff I don't like: all the stuff in the rules here anyway, plus herms/she-males are a personal squick (I like both girls and boys, but only seperately, not in the same body).
I'm pretty open to most other stuff, even if it's not big on my list. It's fun to give other people a good experience too, right?
Anyway, hope this isn't too broad. I just hope some GMs see it, even for games that are already running or whatever, and mebbe I can get in on something! Yay!