In most modern environments, victims of assault are typically attacked in urban areas and often need to fight off more than one possibly armed opponent. In many circumstances the safest way to get out alive isn't mentioned, which is to simply walk (or run) away. Many train extensively on how to face off against someone and don't bother trying to escape or to disarm the situation with verbal tactics. I strongly suggest, before learning any type of self-defense techniques, learn to run and move with agility and swiftness. If you ever need to face a drugged up hobo with a dirty needle in his hands, you'll thank me.
If you absolutely need to defend yourself by attacking the other individual, there's no time and place for silly, over the top moves that take years to master. You need something proven, that works on any type and size of person, and that will work instantly to help you get out of the mess your in. I've practiced many martial arts including Karate, Boxing, Tae Kwon Do and Iaido, and personally find some have become more and more stylised with time. Many of the best no nonsense martial arts come from modern military trainings and we're going to check them as well.
The Marine Corps Martial Arts Program (MCMAP) - Based on various classic martial arts such as Okinawan Karate, Jujutsu and Judo, this program focused on taking down (and taking out) an oponent as simply and quickly as possible. It also touches on the mental readiness factors as well as teamwork, and responsible use of force.
Krav Maga - of Israeli and Czechoslovakian origins, Krav Maga (meaning hand-to-hand contact) focuses on grappling, striking techniques, and brutal counter strike techniques. It's origins come specifically from street fight self-defense and is renowned for targeting the most fragile body parts such as eyes, throat, groin and nose. It's style integrates a lot of different influences, from Muai Tai to Jujitsu.
Mixed Martial Arts (MMA) - Although this style is more of a sport, it's RBSD (Reality Based Self-Defense) factor is strong. It's origins come all the way from Ancient Greece coliseum fighting, or Pankration meaning ''All Powers'', a fight in which opponents could use all and any possible techniques to win. Modern MMA has become extremely popular in recent years, and a few minutes into a fight, anyone will immediately notice fundamental differences between it and other classic styles of martial arts such as Karate and Tae Kwon Do.
Jujitsu - Know as the art of manipulating an oponent's strength, power and weight against himself. Jujitsu classes will teach a variety of grappling techniques, gouging, biting, joint locks and holds. Many other styles take from this Japanese art and its only drawback in street fighting is that one often ends up on the ground with the opponent, which is to be avoided in instances where there are several attackers.
All these techniques were designed for fighting, but it's worth mentioning again that the best self-defence is verbal technique known as verbal judo and to walk away. Sometime one's pride will hurt, but it's better than getting seriously injured or killed.