I'm probably wrong to comment here. I gave up trying to maintain an organized music collection. It takes lots of effort and/or money. I just throw everything I have at Windows Media Player and let the chips fall.
For casual exploration of music I use Rhapsody and just pick what I want to listen to off their service. It's kind of like having millions of tracks available on demand. Well, in fact it is.
But, it's no sonic utopia. Invariably, there's always at least one song I want to hear that they don't have rights to stream. Or, their really poor search and presentation facilities make it impossible to find what you're looking for.
Still, you can listen to Rhapsody radio for free, and pick 25 songs from their menu for free each month. Honestly, that's more than I usually use.