Okay, there seems to be a consensus developing in this thread: The word unconscious is a more clinical, academically acceptable term with a relatively narrow meaning of not available to the conscious, encompassing both "knocked out" and "unaware". The word "subconscious" is a more popular term, less rigorously defined. Unlike "unconscious" it implies some connection to and ability to move from and to awareness.

A quick perusal of wikipedia seemed to confirm this; the article for unconscious was relatively well developed and supported, while the article for subconscious "tasted like fairy floss", as one person on the discussion page aptly put it.

My interest is along the lines of the current pop culture self help idea of getting in touch with things within my mind/body which are drivers of my perceptions and behavior but which are not usually at the level of awareness. I do believe it possible to access and mold this subconscious through conscious actions, so I think I will use the word subconscious in my discussions, even though it's a word that academics don't find rigorous enough. The movie 'inception' is a good example of what I'm talking about when I will use the word subconscious.

The Freudian term preconscious seems to mean roughly the same thing as subconscious and is a bit more academically rigorous, but because it is not widely used outside of Freudian analysis, I think I would confuse people by using it for my pop-culture understanding.