Well, I'd have to say look for the Chinese arts..........Kung Fu would fit the bill depending on who's teaching. Kung-Fu encompasses such a massive variety different arts, that it's really not an art in itself. There are so many different types of Kung Fu it isn't funny. But typically hard chinese styles, in my opinion, are the best because they create power while still remaining fluid. Karate for instance is VERY powerful but way too mechanical. Picture the Karate kid......he'd get his ass beat silly 99 out of a 100 times by ANYONE that knows ANYTHING about fighting.......he might beat a one legged cripple though.
And also, stay the fuck away from schools that 1. put ALOT of emphasis on belts and 2. put emphasis on tournament fighting.
When you get into a street fight you will fall back on your training, and you will not make the distinction between what they tell you to use in tournaments and what to use on the streets. If you train for tournament type techiniques, that's what you'll use on the street. But on the street you're not wearing protective gear, there's no ref, and the other guy is going to walk right through your "scoring" strike. Train to hurt people as much as you can in the shortest amount of time possible.