Johnny because he's a ****ing idiot. Sue considers herself to be the most amazing scientific puzzle she's encountered and intends to dedicate a great deal of her energies into solving that puzzle, while johnny knows that he can say "flame on" to flame on, and "flame off" to flame off. And that's pretty much all he knows
Reed was a close second because I know what it's like entirely to get so wound up in something so utterly meaningless to others, and to totally miss the point of why they seem to be bothered about it.
There really aren't enough 'uncool' heroes, and johnny is the best of the bunch by far. The guy is such a dork. But a likable one.
And ben, the interactions with him and reed are very amusing, there is a definite love between the characters.
Hell, it really is near impossible to select a favourite, they work in ensemble so damn well. A testament to the writing.