My music collection is 84 gigs right now. I know it seems like a lot but I've listened to and know 99% of it. I keep a giant playlist in WinAmp of every song, and I usually just randomize it. Then I pick the first 500 or so songs to put on my iPod Touch (8gb). Sometimes I want songs that I know/like especially, so I keep another playlist of those, and I randomize it too. How big is your music library, and how do you manage it on your iDevice?