The martial arts I would most like to to pick up would be: Muay Thai (boxing-like with knees, kicks, and elbows), Judo (Predominantly throwing and grappling with some submission fighting), and Brazilian Ju Jitsu (Predominantly submission fighting, also some grappling and judo is involved.) I would also highly suggest no-gi over gi style in both judo and BJJ (if possible), as no one you ever fight in real life will be wearing a gi. I am a black belt in Tae Kwon Do and find it pretty much useless in terms of self defense. I legitimately think I've learned (far) more about self defense and fighting from watching UFC and Pride FC than I ever learned in Tae Kwon Do. To me TKD is better for kids as the only thing it is good for is discipline.