If you have the opportunity, muay thai is an excellent thing to study as far as protecting yourself in a street fight. Teaches you distance, mid-range, and close range striking, as well as how to utilize your elbows/knees instead of just relying on hands. By simply following youtube videos long before I started training I managed to develop a pretty nasty elbow, and in a self defence situation, it didn't let me down; one hit and he was out cold, than I got the hell outta there before anyone else decided to fight me.