What is the coolest, toughest, best, and most skilled form of martial arts to study?

I want to know which form of martial arts would be the best to study: Muay Thai, Kung Fu, Tae Kwon Do, Jiu Jitsu, Brazillian Jiu Jitsu, Judo, Shotokan, Karate? What's your opinions on this matter and what do you recommend most for a person to study