Ratskinner
Adventurer
A friend of mine expresses concern that getting mechanical benefits for bringing weaknesses into play encourages artificial role-playing in the form of picking weaknesses just for the benefits. He cites people doing exactly that in new World of Darkness games.
I think that's more a problem for games that don't offer some sort of in-play currency for the benefits.
In FATE, taking a "bad" aspect specifically to get it compelled often and earn a lot of FATE points is fine. Presumably, you would then take that pile of points and use them to power your "good" aspects, as well as invoke aspects on the bad guys, etc. Which works fine, you actually have to take your lumps to get the points. You actually get players looking for ways to get compels and even suggesting them. Contrast that with a system like GURPS (or Vampire IIRC), where there is no currency, but you earn build points for "disads". In such a system, you are encouraged to try to avoid taking the lumps for the disads (both in-game and at-table) because you already have earned all the benefits you will ever earn and can utilize those benefits freely.