It seems to me that Clerics and Sorcerers should always take a PrC. These core classes only have turn undead and familar advancement as their class specific abilities. Why in God's name wouldn't you rather have the cheesy special abilities of the various PrC?
Has anyone in your campaign stuck with a straight Cleric or Sorcerer?
Has anyone in your campaign stuck with a straight Cleric or Sorcerer?