I would want to be Tsukune from Rosario Vampire, after he gets his powers. Or maybe Kenichi from History's Strongest Disciple. With these two you get to be strong/powerful AND have girls.
I would like to be keima katsuragi from "the world only god knows"
pro in gaming, expert in study and easily get a girls heart
wat more can u ask... ^^
He has the ability to wield a sword and operate machinery intended for battle and be good with it without any special talent or training due to the ability bestowed upon him for being Louise's familiar, so I could really kick arse. Not only that, but having a harem is a man's ultimate dream, especially when one of the girls is your waifu.
Orihaya Izaya from Durarara: Loves humans. Knows humans. Knows how to push peoples buttons, knows how to manipulate humans.
Masaomi Houzuki (Old Man ver.) from Sharin no Kuni, Himawari no Shoujo: Stare of Fear, menacing, provoking, even though he's old he can still kick ass.
Azai Gonzou from G-senjou no Maou: Same as Houzuki except he's not old. He's big and burly.