Ok, without a doubt the coolest male to ever grace (or kinda grind his own way through) a manga is of course Eikichi Onizuka, 22 year old virgin, and Great Teacher Extraordinaire.
As for Female, that's tougher. I'll currently cast a vote for Excel, because the crazy psycho henchgirl is the funniest thing I've seen.
"Haaaaaiiiillll Ilapulatzo-sama!"