I'd say Sanji since he's kinda underdog and more honorable han Zoro. Zoro only fights for himself and to become the best neverminding if someone except the others are in danger as long as he dont want to fight a swordsman. Sanji fights if a girl is in danger, when he get's beaten up, he lights a fag and gets flaming feet, goes champloo and kick everythings ass... He is way more badass, since we know he also can use knives as weapons due to the battle against a chef at the puffing tom.