I'm currently playing a character whose only weapon is his shield (okay, not only weapon, but he usually fights with just the shield alone, and nothing in his other hand). And I have to say, Shield Charge is a really good ability. It combos well with power attack (+2 dmg for every -1 atk), and when you throw divine shield in there... ouch. Throw in a smite evil for a little extra (doubled) damage, and you definately have a winner there.