You need to do a couple years of boxing and then you'll have a solid base for any other marital art you desire to learn... pun intended.

Hate to be irrelevant but...Krav Maga is the best thing if you really do just want to defend yourself. The problem with Krav Maga is that it teaches you to KILL the other guy. Krav Maga isent really a sport, it was developed to kill/disable an opponent very fast and with mimum damage to you.

Krav Maga dosent take that much training for use against people that arnt trained in martial arts. I have very very little training in it, but the principals as I gather them are:

1) Agression. There is no pure defense in Krav Maga. You deflect incomming attacks and strike back at the same time.

2) If you do attack its full force to weak points- groin, eyes, throat, back of the neck.

3) Nothing is "below you". If you have a gun, shoot the attacker. If you have a lead pipe hit him with it. Bite, scratch, claw, anything.

4) Never ever stop fighting.

Yes, sounds obvious but when you train for its and you fight several opponents one after the other, with no weight classifications, its damn hard to stay agressive.

Some of the moves take really little time to learn and make a habbit of. The problem is if the other guy has training. Beating up an untrained opponent is "easy".

I'd say someone with 3 months of intense Krav Maga training is far more adept at defending himself than someone with 3 years of say, Tae Kwon Do.
Personal experience really.
But the one problem I had with Krav Maga was, what if it's a little iffy to actually try maim the guy?

thats not a small probelm, it is a huge problem.

Yeah, so if it's a situation that poses a real problem, you know exactly what to do.
If it's iffy... your ability is hampered by the confusing ROEs.

THAT is the only problem I see in teaching Krav Maga to someone who is <25... they don't have the discipline or wisdom necessary to control its use.

Great point. Yeah, no Krav Maga.

as i said i was taught Krav Maga in the military. On the other hand I have seeral friends with eyars of experience(yes, they have classes from age 10), and they havent broken one of my wrists so far. I have to say they do hurt me badly sometimes because Krav Maga teaches you to find a joint and bend it fast and hard till it breakes

Truth is, I don't put a lot of faith in those joint things that are somewhat reminiscent of Aikido.
When was the last time you won a fight like that? Never?
Doing non stop attacks on various weak points of the human body, now that works. Putting "set piece" combinations together so you can use them when necessary. That way all you have to do is "pull the trigger" and the rest is automatic. If you're thinking about your next move, you're already too slow.
Great thing about practicing "set pieces" is that your body is already accustomed to moving in a certain pattern, you get to fix parts where you feel delivery is slowed down because your body just doesn't move that way very well.
As a situation gets bad, you already pick out which set piece you want to use and when you decide that now is the time, your attack combination will be so fast that I doubt anyone could react to it. The moves should always be simple and never compromise your center of gravity (GREAT thing about Krav Maga btw that Tae Kwon Do violates in spades).
The only real arm twist thing that I think has any chance of success is taking advantage of someone's right handed punch because most folks will launch the right handed punch to the face as their first choice of attack (about 70% if I'm not mistaken). Of course you'll have to practice this A LOT with a friend or partner with a glove who at first goes slow, then volunteers to punch your lights out.

when i was talking about joints i was refering to knife/pistol disarms.