If you go Cleric, you can have an AC rivaling that of the fighter, good hit points, good fort and will saves, and access to so many good combat spells.... scratch that, access to so many good spells.

Divine Favor, Magic Weapon (and Greater Magic Weapon), Bull's Strength, Bear's Endurance, Shield of Faith, Protection from Evil...

Then there's Domain Powers, which bring a whole new level of awesome to play.

"Oh crap, I failed the save. I guess I'm dead now... but wait! I can reroll one dice roll once per day!" - Luck Domain.

Also, obligatory link when arcane casters are mentioned in any thread:
http://www.giantitp.com/forums/showthread.php?t=18500