i've got around 20 gigs of music, and i don't have anything i havent liked the last 8 years or so. Of course i don't listen to all of it anymore, but i don't see a point in deleting them, might be good for something one day.
I have 1506 songs on my iPod, but I know a guy who just downloads pretty much every new album that comes out. He has over 40,000 songs. When I asked him about it he said: "Well, I never listen to the majority of them, but when I take my iPod to a party there's always something for everyone."
on my laptop I have, 48.7 days, 81.4 gigs. on my externals, I have nearly a terabyte of music and 3 TBs of movies. I have seen every single movie, but most of the music is half listened to. I listen to parts of songs, never the whole thing, and I can usually pinpoint artist after hearing a song once.