Basically the techniques used commonly in Mixed Martial Arts.
Muay Thai, Boxing, Wrestling, Jiu Jitsu. Anything else is just bonus IMO.
Krav Maga or anything the SEALS train is relevant to combat you may face in a real situation and in a life or death situation. Also weapon disarming
is excellent to know.
Kendo or Kali - Although a weapons based martial arts they make use of staffs or sticks which can be formed out of anything.
Judo or Aikido - Very close counters can be easily manipulated with a good toss, trip or take down.
And learn as much joint manipulation and submission techniques, escapes, reversals,sweeps etc because you aren't always gonna have someone relative
size or strength to yourself so having a strong bottom position is crucial if someone larger is going to mount you (sounds dirty i know)
edit on 28-5-2011 by eleventhsun because: (no reason given)