So many characters, so many choices!
But there are a few generic preferences. Since you can enchant clothing to provide magical defence, many, if not most, of my characters do so. My "Orc with a Battleaxe" character wears leather boots, laced leather pants, and doesn't bother with a shirt or hat/helm. That still means two ring slots, an amulet slot and two clothing slots for frost/fire/shock shield and the Transcendent Sigil Stone variety only needs three of those for 75% armor rating. Blossom, his female counterpart with the more dainty one-handed axe, used reflect damage and spell enchantments to get her defence another way. Her velvet dresses and shoes didn't get enchanted at all.
My mages generally dutifully wear their assigned robes while they're doing the guild quests, and then find something more fashionable to enchant after they graduate. Half the members in the city guildhalls wear "civilian" clothes, too, so it seems appropriate.
Archers all agree on lightweight and sneaky stuff, and several of them carry the
Bow of the Mongolian Horseman just because it looks like a real bow. I usually have them decide what existing bow's stats they like, and then substitute the model for their game only.
Clark wears Green Finery from the Shivering Isles, and gets his defence from reflect enchantments (such as the Escutcheon of Chorrol and Ring of the Iron Fist). He's usually got a companion to help with the offence, but he'll use a shortsword when it gets close.