I tried briefly with an evil cleric, with the intention of dual classing to necromancer. I got all the way through the Vale of Shadows before it dawned on me that I'd be using a first-level mage in Dragon's Eye.
The thing I despised about soloing was the reduced ability to carry things and use cool items. I prefer dynamic duos and terrific trios.
Cleric/Ranger and Fighter/Mage/Thief are a great combo.