Wizard. You have the most versatility and you are basically a bard, cleric and summoner all in one. The wizards ability to buff, debuff, and summoner. With the debuff you hurt the enemy therefor helping your friends. With the buff you help your friends thereby hurting the enemy and when you summon (if you choose to do so) you are basicaly adding another low-level fighter that can have spells and other abilities ( aka Bralani azata). Check out Treantmonks Guide to Pathfinder Wizards: being a God.