I tried everything through (well ... most basic set-ups) before I settled on a mage (whom I gave arcane warrior and will give spirit healer). I use glyph spells, ice spells, and paralysis spells. So yeah, I like disabling my opponents and letting Alistair, Shale and ... whoever else I feel like at the time do the damage. After all, I tend to need to meticulously control the mage any way, so I may as well make her my main (as I tend to control the main as it just feels .... right, to me anyway).
EDIT: I should probably add that I thoroughly enjoyed my shield-axe dwarf character, as the stun and knock-down effects are always helpful, and unless I am just some kind of freak of nature, the shield-bashing type attacks tended to shatter enemies more easily than regular attacks.