I have a black belt in tae kwon do, a purple belt in kempo karate, a blue belt in Brazilian Jiu-Jitsu and have trained in wing chun, shaolin kung fu and capoeira.
I like Brazilian Jiu-Jitsu the best, it's very humbling and physically challenging.
But all the arts have been very fun, I like to go dancing and do gymnastics so capoeira is great for that. Wing Chun is pretty cool, learning to use your hands quickly and deflect close range strikes. Shaolin Kung Fu was fun, we would do flips and intricate forms and tae kwon do/karate had me throwing all sorts of head and leg kicks, got me very flexible and in very good physical shape.
Oh, I forgot I've also trained in qi gong and tai chi quan -- tai chi is pretty dope, you learn to move with a lot of grace and fluidity.