What is the most under-rated dual or multi class, i would have to say it is the cleric/thief which i like the most and the cleric/ranger also seems under-rated as well, if im wrong post away and tell me.

You are probably right, I have never even thought about using them...

Try this....a multi or dual Fighter/cleric gtrandmastered in flails and war hammers....dual weapons....freakish damage plus cleric bonusus....especially high level like aura of flaming death and try reaping some havok.
Ns.

The problem with Cleric/Thieves is their poor selection of Backstab weapons--Club and Staff, and you've got to drop your shield if you want to use the staff. Finding Traps while wearing armor is nice, but Fighter/Thieves can do that too. Also, due to the scarcity of bottom-row buttons in BG1 (I don't know if they've changed it in BG2), Cleric/Thieves could only have 1 Quick Weapon, and you had to go to your Special Abilities menu to get to the Thieving button. Overall, Mage/Thief is much better combo.

I don't like Ranger/Clerics because they level up so damn slowly; the only thing slower is a Fighter/Cleric/Thief. Sure, Ranger/Clerics get both types of Priest spells, but you still have the same # of spells to memorize. Not worth it.