There are heaps of great music-steaming services out there, now that, apparently, music is free. Really, they should be used as over-qualified previewers in determining which LPs or CDs you really need in your collection, if permanence and sound quality matter to you. Among them,

Spotify: of which I might be a terrific fan, where it legal in Germany, where I am currently living, but alas, it is not.
Pandora: the great pioneer and game-changer that plays a virtual radio station built on a matrix of similar-sounding artists. A great service, but it won't play an entire album, and I've never been much of a singles guy. Also illegal in Germany.
Naxos: this is the largest classical record label in the world, and they're buying up smaller companies by the cello case to add to their online streaming service. It is a subscription service, so you pay for access to their 800,000+ tracks but can stream them at CD quality, if you have the bandwidth. They also have a pretty deep bench when it comes to jazz.

But my favorite of all, by a good long way, is

Rdio: Another subscription service (my plan costs something like $6 a month), Rdio features the best interface of the lot, tons of obscure recordings, a social feature that is (for once) actually useful--I'm not talking about updating one's facebook automatically every time a new record comes on, but the "playlists" feature, where some pretty tasteful people put together great jazz mixes, Christmas tunes, KEXP-based melodica, and other turn-ons for this traveller.

I came to Germany with 3500+albums on my iTunes, but sometimes--however absurd it sounds to say it--that's not enough. I don't know how I managed to cross the pond without a copy of Straight Six, by Poor Old Lu, or with the better of the two perfect Mineral albums, but I did, and Rdio was there to rescue me.

In addition to turning me on to bands like Wye Oak, and Cults, Rdio has been a treasure-trove of old favorites: Jeterderpaul, anyone? Joe Christmas? The mind fairly reels.