Most people like fighter/mage/thief or fighter/mage/cleric, but i think that if you dont remove the xp cap, it would be very difficult to complete the game using them. Im currently playing a solo sorceror. Ive removed the xp cap, and i dunno if i would have been able to complete some quests without having removing it, cause inprisonment has saved me so many times.
I really think that sorceror is the best one, due to his flexibility casting spells, but you might want to try one of the above, or a monk (i heard this one is very succesfull too).
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"TEEHEE !!!!" -
The Mighty CloudQueen, to Ertai