There's an interesting article in the LA Times in which Randall Roberts ponders the impact that streaming and download services are having on traditional notions of music "collecting." This is something I've been thinking a lot about lately, and if I ever get a few spare moments to organize my thoughts, I'll share them with you.
In the meantime, I recommend reading Roberts' piece, which is very good. How have services like Spotify, Rhapsody, iTunes, MOG, Google Music, etc. affected your music purchasing and collecting habits? How have they affected how you think about your music "collection"?