Cleric/mage followed closely by a fighter/druid [img]smile.gif[/img]
I found the assasin to be rather boring ( backstab, run .. backstab . .pick up Boots of speed .. backstab, run real fast .. backstab ) after a while.
Priest you already solo-ed once and a mage/thief doesnt do anything but either create a mage that hides in shadows or a thief that goes invisible more often.
So Cleric/mage or fighter/druid IMHO. And Cleric/mage taking the cake.
Fighter/druids will probably end up mostly fighting with some buff-spells and summoning stuff on occasion. The Cleric/mage has the oh-so-wonderfull ability to be a mage and a cleric at mage-casting-speed ( important with Robe of Vecna etc. ) and once in a while be an untouchable tank
