The nice thing is that, in this situation, assuming that everyone is playing to their generic role and the fighter isn't an archer, the wizard an aspiring fighter/mage, and the cleric another archer or a self-buffing fighter, you can play anything you want and contribute. All of the bases are covered.
So either get some descriptions of the characters histories and personalities and craft a nifty hook to bring another character into the party or just put together a character you want to play. As for myself, I've recently enjoyed playing fighters and clerics and suspect I could have a lot of fun playing a paladin to type rather than against type (as I'm doing at the moment). However, I've often thought that a skald type bard--possibly aiming for Warchanter (Complete Warrior) would be a fun character to play. So I think I'd play a combat focussed bard, possibly multiclass with fighter and/or barbarian a little, and have some fun as a second-rank combatant and general support character.