Well I love my 6 heroes based team and I think I will not stick with NPCs anymore (except the one needed for quests), I want all the XP. But for me NPCs are:

1) Good for a strip! :D
2) Boost some communication skills.
3) Back support when fighting in the same place.
4) Some extra XP if you are Evil :D

One interswting thing is when you strip a NPC, s/he will still atack foes with her/his melee weapon, even naked. [img]smile.gif[/img]