[markem]

It is entirely possible that, for your system, random play does not equate to creating a random play list of all the songs. Some systems pick a new, random song at the end of the currently playing song. If that is the case, then under a random system, never being picked is entirely possible.

For my iPod, I tend to create random play lists and then play those sequentially as I get better results (for me) than random play off the computer or other media.