[click170]

Those just aren't sufficient IMO.

I like being able to listen to music when I have no internet connection.

I like being able to listen to something when the original was taken down.

I like being able to listen to something that the vendor no longer offers.

I like having smart playlists in my library and on my devices that automatically update themselves based on meta data such as what I've played recently.

Unfortunately I like being able to use my music program on an operating system of my choosing as well, and am looking for an iTunes replacement. But then replacement can't be worse than the original. That's a deal breaker.

[tschuy]

Spotify premium, uploading anything they don't have, and using Offline Mode?

[daveid]

Buy CDs, rip them, and listen to it on any player you like. Or when an artist does not release CDs, they usually at least have a Bandcamp where they offer FLAC downloads, DRM-free.

[derekp7]

Isn't most of the music purchases on Amazon DRM-free? And downloadable in regular MP3's with a standard web browser? It's been a while since the last time I acquired any music.

[javert]

Yes. I purchase Amazon MP3s and play them on Linux. I like actually owning my music as good old-fashioned files. Highly recommended.

Amazon doesn't just provide a link to the files once you purchase them, there is a downloader client. I have never tried the official one, there is an open-source command line alternative called "clamz" that works perfectly.

[kissickas]

Have you tried Google Play Music? You can start by uploading 20,000 songs that you already own and just sync them to your phones/computers for offline listening.

[antihero]

Other than smart playlists, your requirements describe pretty much any media player released in god knows how long.

Personally I usually have an internet connection except on the train, so I use a Subsonic server, and my Android Subsonic client is set to aggressively precache my playlist (so it plays happily through tunnels, even if the tunnel lasts 10+ songs).

[AndyKelley]

Have you tried groove basin? It satisfies your requirements except for smart playlists. But that feature is planned :-)

[unicornporn]

Won't fit all of your criteria, but foobar2000 is wonderful. Works well under wine in OS X.

[munificent]

Maybe not for you, but the original question was what do other people use.