You can get some good stuff from sport martial arts and real martial arts as well. Growing up in a Town most noted for it's prisons I've kicked some butt and had my butt kicked and I will tell you that all the martial training in the world isn't worth a thimble full of experience in actual HTH.
My suggestion is to learn and practice practice practice the basics of as many arts as possible becoming an expert at only the most simple and powerful techniques. You will find only the simple stuff ever gets used in the real world. Some art's like Thai Boxing are designed on using simple techniques effectively. Do not neglect ground fighting and traditional wrestling techniques as most real fight's go to the ground quickly.
In General, learn hand techniques from japanese and southern asian styles, learn foot techniques form the Thai, Koreans and Northern chinese stlyes, learn throws grappling and Joint techniques from the Japanese stlyes and Greco roman wrestlers. Throw in a little all American bad attitude and you've just tranformed yourself into a can of whup ass!