Wes. For all you people who either don't have Colloseum or don't have a brain, I'll explain.
He isn't the same ten year old who goes on a journey without a motive and who just happens to come across an evil team and beats them because he doesn't have anything better to do. Wes is an ex-Snagem, the most evil team besides Cipher, member, who probably disbandend Snagem because they worked together with Cipher. He has just one goal and that is to stop Cipher.
He has a huge motorcycle. Just that makes better then everybody else except for Miror B (Miror B>everything else>Pikachu).
He is the only character that actually has a stalker of the opposite gender (no, rivals and Scott aren't stalkers). Rui gets anoying after some time, but she still remains to travel with you even after there aren't any Shadows left.
He's an ex member of the second most evil team known to men. Not only that, he blew up their head-quarters and stole the portable Snag Machine from them.
He still has tales about him five years after he beat Cipher. Not only that, he mysteriously disappeared. He'd done his job and didn't need to stay around any longer. Unlike Red who still wants the spotlight three years after his height.
He beat Cipher together with a girl who did nothing but locating Shadow Pokémon. For you people who don't know, Cipher is the strongest and most evil team:
-In Colloseum they captured three legendaries and in XD they captured four more.
-They controlled an entire region.
-They nearly captured Celebi.
-They created Pokémon who attacked humans so that they could conquer the world.
-They build a gigantic tower. That shows how rich they are.
-They had Miror B as an admin.
Those are just a small percentage of reasons of why Cipher is the most evil team. I could go on for a long time about why Cipher owns and the other teams blow, but that isn't what this thread is about.
My post in short: Miror B>Wes>everything else>Pikachu.