I am almost exclusively audiobooks, but I do occasionally read as well. Audiobooks let me "read" while doing almost any other activity that doesn't require too much concentration: yard/house work, driving, exercise, etc. I'll even fall asleep to audiobooks from time to time. I've gotten my dad into audiobooks recently; he tells me that he feels less tired after a long drive (vacation travel - retirement must be nice) when he listens to a book vs. listening to music. I suppose audiobooks is a more "active" way to pass the time and helps you to maintain your concentration, but I'm no expert.
I can't believe someone actually voted for "This is MobileRead not MobileListen." Man, that is just rude! I would like to think this is a place for anyone with a love for books.