I would absolutely recommend any martial art to anybody. I did Brazilian Jiu Jitsu and Mixed Martial Arts, and I was in great shape, super confident in myself, and just all-round having a wonderful time in life. For practical purposes, those two will give you everything you need to successfully defend yourself from the most common types of attacker, which is a nice thing to know.

Any martial is an excellent idea, however. Boxing, kickboxing, muay thai, tae kwon do... doesn't matter. Just try a few different ones and find a group you enjoy.

MMA, BJJ and Muay Thai are my top three for being the most fun and the most practical, though.