Are viruses zombies?

Are viruses alive? Dead? Dead-alive? ACSH's Dr. Josh Bloom posed this question last night on the new ACSH-sponsored Facebook page, Infectious Diseases and Vaccines, with the promise of a Snickers bar for the best answer. He got a ton of responses, including one woman who wrote, They don t contain all of the structures and biosynthetic machinery necessary for reproduction. Their genome is mostly DNA or RNA, but not both like most organisms. Viruses do contain some enzymes and encode others as well as structural proteins used to assemble new virions, but they rely on the host to create new energy. Undead!<P>
Kinda like zombies.<P>
Someone else added, Since biology has exclusively encompassed the term living into subcategories, which all must be met in order to be considered as living, I think it safe to say viruses are not living. They can only reproduce if there is a host cell, and because of this virologists do not consider them to be alive.<P>
Dr. Bloom adds, That was a pretty good answer, but I decided to eat the Snickers Bar myself. Life just ain t fair sometimes.<P>
So what do you think? Viruses: Zombies? Dead-alive? Creatures from another planet? Check out Dr. Bloom's answer and a lively discussion on his Facebook page.