I'm afraid I can't agree with Shieldbearer, Totemic Might and DEFINITELY Nozdormu.
Shieldbearer, with a 1 cost is quite decent even with 0 Attack. Put this guy in a Shaman, Paladin or Priest deck and you can make him a very useful guy for a low cost.
As others have said, Totemic Might is definitely a good card for the 0 cost. Some totems are definitely worth it to health-increase and thus increase chances to keep on the field. (Flametongue Totem, Healing Totem and the Taunt one, for example.)
And Nozdormu... a No-Brainer. If I had this card, I'd use him in every deck I owned. Some people seriously take ages even when they cannot do anything anymore. A true pain in the ass.