Hmm....

Furious: High Strenght, more movement then Conquista, but Immune to magic and basically all physical combat.
Sam: Helped us win last battle with Manaflare, but otherwise he's mostly a team player and not too great on his own.
Conquista: Hellfishy is currently our most powerful spell in our arsenal damage wise that inflicts all the damage in one turn (not counting spells like Foshizzle which damage depends on certain variables), and her attack is nearly as much as that of Furious, but her movement point (1) really brings her down, and she has only two spells, both of which are damage inflicting (no boosting/raising or whatever)
Fooruman: Has Raise, Heal, Foshizzle (which can deal a lot of damage; more than hellfishy, if cast at the right time, and other useful spells. Currently, I'm also leaning towards Fooruman because he has both spells that inflict damage and that help the party making him more of a 'diverse' character.

Right now, I think it's pretty much unanimous that Fooruman will be the one picked, though I suggest waiting for more people (White Rabbit, for example) to reply to this before making the final decision.

Question: Can you switch the characters you pick? (ex. Pick Scholar Sam, but then return to wherever later on and switch him for Fooruman if you find that he's not as effective in situations)