What's funny is, the "One true" or the "best" martial art has changed a LOT over the years. Whatever is the new buzz word popular martial art, that's the "best" one to people who like to talk in terms like that. Currently, at least in my opinion, the three popular buzz martial arts are Thai Boxing, BJJ, and Krav Maga. Krav Maga is the latest (latest meaning it's really only become really popular fairly recently, even though it's been around for a while) "exotic" foreign special forces ultra cool secret martial art. Before KM became e-popular, I used to hear a lot about Systema from the same kind of people.
I see this on a lot of non-martial art forums when the idea of best is brought up. The topics generally go like this:
OP: What's the best martial art?
Poster1: BJJ! Look at the Gracies!
Poster2: Krav Maga... the Israeli Special Forces do it, and those guys are the bestest ever in the history of the world!
(generally poster2 has never studied any martial art, much less KM)
Poster3: A combination of Muay Thai and BJJ. Every Mixed Martial Artist in the world can't be wrong.
Poster4: Whatever it is, don't do Karate. Every Karate guy ever got his *** kicked in the octagon.
Those same posters often times overlook how Wrestlers do fairly well in MMA overall (Randy Couture, Matt Hughes are excellent examples), and how some guys like Lyoto Machida see great success coming from a Karate background.
Try as I might, I can never convince any of the above opinion holders that there's no such thing as "THE BEST." Each person is going to draw something different from every different martial art, and simply knowing a particular style isn't going to automatically make the person a certifiable badass, so the entire concept of a singular best style is flawed from the beginning.
It's especially flawed when you step into the competitive world. , When when you get into the ring/octagon, a punch is a punch and a kick is a kick. Sure, you can see the differences between a Thai style fighter (the big wind up before the leg kicks, for example), and a Karate style, but neither guy is going to have any advantage over the other simply for their chosen background. But if everyone knows one particular style, everyone knows what everyone else is training, so the guy who does something different now has an advantage... Like Lyoto Machida again (even though Shogun completely dismantled him last night). He had such a weird stance and such a different style of fighting, no one knew what to do with him. He even knocked out Rashad Evans. Same with the entire Gracie clan. In the beginning, no one knew how to fight them... now everyone knows BJJ, so even if they weren't too old to keep fighting, they wouldn't be dominant anymore.
The point is, the STUDENT makes the martial art... not the other way around. Simply having the tools doesn't mean I can use them effectively. There are many many other factors involved, and people all too often oversimplify everything, and distill it down to a point it insults the entire world of martial arts by completely ignoring the finer intricacies that distinguish one style from the next.