I've just discovered the music streaming app called Subsonic and I'm very excited about it, so I thought I'd post my experiences with it here.
What's so great about Subsonic compared with other streaming Apps? Well, it allows you to stream at full CD quality your entire music library, to just about anywhere. At least full CD quality will work reliably, I've found, as long as you're on a WiFi network. One user on the Subsonic forum reported he was even able to stream full CD quality over a 3G network.
Subsonic is really built to handle large libraries of music and allow them to be streamed to multiple users at the same time. I haven't tried with more than 2 -3 users within my family at CD quality; but I don't intend sharing my library beyond a handful of people anyway. On the Subsonic forum you'll see a lot of talk about transcoding. This is because most people want to be able to reliably stream to IOS or Android phones while on the move and the only way they can guarantee reliable streaming in those situations is to have the Subsonic server transcode wav, aiff or lossless formats like flac to MP3.
Turn transcoding off though and Subsonic just streams the original file, whatever format it happens to be in. To guarantee reliable streaming, I'm in the process of creating a copy of my entire library in flac with an ogg wrapper with compression set at max. There is no loss of quality with this method over the original CD files. Flac would probably work just fine without the ogg wrapper and Apple Lossless will work fine too. I just wanted to guarantee that whatever program I use in the future to stream from Subsonic it will probably be able to do so reliably.
As far as I know Subsonic is the only technology that allows streaming at full CD quality. My apologies if it has already been discussed here; but I looked and couldn't see any mention of it and like I said, couldn't contain my excitement.

Here's a quick summary of it's advantages and limitations:
1/ Runs on any platform as it's written in Java. This includes running directly on a NAS. It's easy to install on a Mac/PC, a bit more challenging on a NAS and won't run on all NAS's.
2/ Connect using a Mac/PC from any location, using a secured web interface, to your Subsonic server and stream to that computer, playing back on any external player which supports streams. e.g. VLC on Mac, or Winamp, Foobar on Windows.
3/ Connect using an IOS or Android device and stream the music to that device for listening on the move. This might involve some transcoding to MP3 as mentioned above. iSub is the best App on IOS.
4/ Connect using an IOS device and onward stream the device to an Airport Express/AppleTV or (I guess) a SqueezeBox; etc device using AirPlay.
5/ If you have SubSonic at home running on a Mac/PC connected to your audio system, the app iSub running on your IOS device can be used as a remote by putting it in JukeBox mode. The Subsonic server must also be put in JukeBox mode via its web interface. Now the audio will play directly from the Mac/PC to whatever DAC you have connected and you can select the music using iSub.
6/ The developer and forum members are very helpful and forthcoming with advice.
Some limitations caveats:
1/ HiRez music above CD standard may not stream reliably. As usual YMMV, so it's always worth a try.
2/ Subsonic is donation ware; but it doesn't work like most donation ware in that you need to donate to obtain a license that will enable all its features, and you will want to do this. Suggested donation is $20.
3/ If using Subsonic in JukeBox mode (playing from the Mac/PC it's running on) you can only play via its web interface. I would like playback via any program I choose to be possible. Sounds pretty darn good via the Web interface though.
If any of you decide to check it out, I'll be interested if you share your experiences here. I really think Subsonic and technology like it is the future for those of us nomads who want to be able to play from our entire libraries wherever we are.
Geoff