Every class in Diablo 3 has its own specialized weapons and armor. Some of those are really unique, like the quiver or voodoo doll, while others look almost the same as every other piece of armor, such as the Barbarian belt or the Demonhunter cape. The one thing in common is that each of these weapons or armor pieces can only be used by the respective class.
Now I've seen 'flails' in the Live version of the game that say they can only be used by Crusaders, but are there any other items? Also, which items found in the current game were Crusader-only in the beta?