Shield

Shields are generally considered armor, even though they are equipped in the off-hand weapon slot. (As of March 2010, only Barbarians and Monks can dual wield in Diablo 3.) Shields are found in Diablo 3, and can be used by four of the five character classes. Monks can not use shields, for reasons expressed by Bashiok in a pair of forum posts in early March 2010. [1] [2]

Bruce Lee would not use a shield, and neither would the monk.

We have shields. Everyone but monk can wield them.

Of course that’s subject to change.

Barbarian with shield.

For whatever reason, shields are extremely rare in screenshots. Only one screenshot thus far released shows a Barbarian using a shield, and there are no pieces of concept art that show characters using shields.

It seems that shields will not be a very popular item in Diablo 3, unlike Diablo 2 where they were very commonly equipped for their huge defensive and blocking bonuses. Barbarians seem to prefer dual wielding or two-handed weapons, Monks can not use shields at all, and [Wizard]]s can use a special item type, the orb in their off-hand, along with a wand or short staff. Orbs provide offensive bonuses, and may be more popular for the glass cannon style character. It's not known if Witch Doctors have an off-hand item that they'll prefer to shields; something like the class-specific totems favored by Necromancers in Diablo 2. And finally, the fifth character is unknown as of March 2010, but is widely assumed to be an archer/ranged attack specialist, who would have little use for shields either.

Also note that the lack of a weapon switch hotkey in Diablo 3 makes hybrid builds non-viable, and that characters will thus find little use in collecting two different weapon sets, to utilize in different situations.