When my grandson was here this summer, he showed me a Zen Micro, and I dashed out and bought one. Now I can listen to all of my music on mp3, using a device smaller than a pack of cigarettes. I have only around 110 of my own compositions on it so far, plus the entire Well Tempered Clavier as recorded by me, and the Goldberg Variations as well.
The bonus is that I now have an additional place to store my scores and midi files. I have all my Sibelius files and all my Sonar files and the leftover SCORE files on this little gidget. This is in addition to my regular backup on a hard drive. Lots of room left over. I consider this one of the great uses of the Zen Micro, and I guess the same thing could be done with the iPod? Being a great proponent of redundancy of backup, I really recommend this use.