There is no such thing as the best martial art. Every martial art has something to offer. Some martial arts are better tools for accomplishing certain objectives, though. The destruction of an assailant in a wrestling situation or the defeat of an opponent in a kickboxing match each involve specific problems that you must overcome. In each case, certain martial arts provide more effective tools for accomplishment of that particular objective, relative to other arts.
A martial art is just a tool for a martial artist. The martial art won't win the fight. Only the fighter can do that. <important>It's the better fighter that wins the fight</important>, not the supposedly "superior martial art". If you see a promotion for a tournament that proclaims, "Come see Tai-Kwon-Do Vs. Aikido!" then you know that it means absolutely nothing. The best fighter, the one with the best set of attributes, will win the fight.