Thank you for all your answers, people. Let me answer my own questions now, as I forgot to do that...
1. What kind of role generally entices you in an RP?
I want my character to believe in something, and to share a powerful feature with the other players (Supervegeta's Gold Tribe, e.g.). More specifically, I think I'm attracted to lone wolf kind of guys, who are different than the pack that travels together, yet still a wolf like them. (Bloodthirster!)
2. You want to have the option of being a good or bad guy, or is that situational with the RP you're applying for?
Anything does for me. Each character, good or bad, has their beauty for me. It's not about being good or bad as it's come to be, it's about finding that certain something that makes them who they are. As for hurting others, I'm not sensitive. This is a story we're writing, that is by all means fictional. There's no room for conscience here if you want to make a realistic story.
3. Do you think you should be equals with your fellow players IC, or superior and inferior roles are needed?
I do think superior and inferior roles are needed, but if I was the GM, I would personally judge each people separately from their SUs to determine if they are fit for the role. I wouldn't like handing out a superior role to one who's not worth it and/or may get overboard.
4. And if there was this kind hierarchy, would you be able to handle superior roles?
Certainly, I can handle superior roles. I know what must be done and I have a clear sense of direction in each of the RPs I'm in (mostly mine xD), so asserting command would come easily to me. How much I would project that superiority over others is determined by what kind of character I would have IC, not by me.
A word of advice: if you don't know how to handle superior roles, you are most probably not fit for a GM, unless you learn to.