I also find that not only have I been listening to more of the music from my CD collection I'm also listening to more new and new-to-me music.
Between all the free iTunes deals out there and allofmp3.com (and 3mp3.ru, if you're game), AND if iTunes keep giving away free episodes of TV shows ... *
and* if the rumors that Apple is close to striking a deal to distribute movie downloads pans out, I'm going to need a whole stable of iPods.