I've done martial arts for 12 years. It depends what your golas are. Krav Maga is not martial arts. It's close hand to hand combat developed by the Israeli special forces. It works in real life scenarios, but so does street fighting, aikido, except you can learn Krav Maga principles over night. No special moves really just how to use your opponents power and balance against him and end the fight quick.
If you want to take martial arts, I'd look into muay tai or valley tudu. Wrestling would be a good base to start and so would any form of grappling sport, i.e. judo and jujitsu