a. Pencak Silat (Indonesia) b. Muay Thai (Thailand) c. Capoera (Brazil) d. Karate (Japanese) e. Kungfu (Chinese) f. Taekwondo (Korean) g. Ninjutsu (Japanese) h. Jujutsu (Japanese) i. Krav Maga (Israel) j. Aikido (Japanese) k. Judo (Japanese) l. or etc
Even though I hate to choose, If I absolutely had to, I would say Kung Fu. I think its very fun to watch a high level kung fu master show some technique. The most effective in real life I believe are Karate and Judo.
Learned Hung Gar Kung Fu, and I love watching Asian kung fu films. UFC is a lot of fun to watch also.