Now that the excitement over Steve Balmer's iPod comment has died down some, I am curious about what people are filling their iPod and iPod-like devices with since iPod can store 10,000 songs.

Are all the iPod users filling up their iPods with purchased songs or songs from their CD collections?  How many of us have 10,000 song music collection?  How long does it take to rip that many songs?

Does 'fair use' allow a user to fill his or her iPod with songs bought by friends and family since all those songs can be borrowed?  What is the reasonable degree of separation for 'fair use'?

Inconvenience of sharing often drives people to buy their own copy but that inconvenience doesn't exist for virtual goods.  Does the law allow simultaneous use of copyrighted goods?

Update:

I just realized that increasing popularity of podcasting means iPods will have two very different types of content: transient and permanent.  As to what implications this might have aside from UI related issues, I have no clue yet.