I'm partial to a club, but that's because I have a dual-classed Cleric/Thief. I just love the things you can do with these guys (Draw Upon Holy Might/Champion's Strength for backstabbing; at high level: Hide in Shadows, walk into a group of fledgling Vampires, Turn Undead: instant kills; Blade Barrier, Hide in Shadows, walk into a group of baddies who fail their saves without knowing what hit them;...
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