Sonos Alternative for Single Room System

MPD. It runs on Linux. You would need some small Linux box to use as the MPD host. Even an old crappy laptop can work. There are two free Android apps to control MPD. It's very, very good. All of the high dollar playback devices are using some kind of MPD implementation.

http://mpd.wikia.com/wiki/Install

The only cost would be getting a machine to run MPD and your time.

I like the Cambridge Stream Magic 6 for a stand alone media server. I'm not sure of its cost compared to Sonos, the Cambridge is $999 but it includes the same internals as the DacMagic +.
http://www.cambridgeaudio.com/summary.php?PID=952

For a NAS, you can't go wrong with a Synology.

If it were me, I would get a 5.1ch+ receiver with DLNA capability so you can listen to your music without needing your TV. Also, make sure it has the uncompressed blu-ray decoding (almost all do now: TrueHD, DTS Master) so when you hook up a blu-ray, you can take advantage of the full uncompressed audio. Your TV already has built-in DLNA video streaming, so you're set there as long as you get an optical cable and plug it from your TV out to receiver in for things like Dolby/DTS decoding and such from normal TV and your streamed videos.

Now all that's left is to decide if/when you want to have surround; you don't need it, but with this setup you could add it any time you wanted to.

The exact internet-based and streaming network capabilities of receivers vary greatly, so do some looking around before deciding.

If you're looking for the best possible network-capable experience, there is no substitute for an HTPC. The best ones you have to build yourself (likely with a Silverstone HTPC case), but there are some pre-made ones as well. That said, you would still need to buy a decoder/processor and amp or receiver because computer sound cards simply cannot compete in terms of DACs (you would use the HDMI out from the PC with digital audio signal to be decoded at the receiver, then video pass-through to your TV).

Be sure to check Denon, they do a lot with network streaming stuff and other features. I know they support the whole phone app and air play stuff.

Now your getting into personal preference territory...

Usually the Onkyo and Denon cram the most features, gadgets, gizmos, and tech under the hood compared to others; but it will depend on model. You'll probably want to thoroughly research all of the models you picked and especially look for forum entries of people who have owned two of them and compared them directly. Denon is probably the most active at releasing firmware updates and what not to fix issues that they find.

As for sound quality, it's going to depend also on how your specific speakers sound paired with the receiver. I doubt any stores will have those exact JBLs around to audition with, so you may call ahead and find some A/V stores with dedicated listening rooms that don't mind if you bring your own speakers in to audition with.

Your JBL LX 500s came in both 4ohm and 8ohm versions; which do you have? I've read that they are pretty power-hungry, so that would make want to lean more toward Denon because the majority of Yamaha and Onkyo tend more toward musicality and features respectively.

This is by no means 100% for sure, because everything differs by model, but usually the companies focus on:
- Yamaha: musicality options, clean power (old Yamahas used to favor brute power like Denon, but that's changed)
- Onkyo: budget, feature pack (usually Onkyo is your best bang-for-buck receiver in that it crams all the newest tech with a good-enough amp at a great price)
- Denon: feature pack, brute power
- Marantz (Denon sister): musicality options, clean power

Alternatively, you may decide to get a receiver that offers pre-amp out to use for the feature pack (various decoding tech, etc) and couple it with a higher quality separate amp, like Outlaw.

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Just as heads-up, I wouldn't consider any of these to be a 25 year quality receiver. These fall into the tech category and give you tons of functionality along with really good sound, but you'll want to look elsewhere if you'd prefer to go with the absolute best sound quality and really long life usefulness. The catch is that most of the really high quality preprocessors and amps are bad keeping up with new technologies.

I believe Rotel is one of the few mid-way makers that tries to balance between staying up-to-date with tech and providing long-term better than par sound/amp quality. Otherwise, you start getting into McIntosh, Krell, etc.

[Edit]
Don't forget to check on Harmon Kardon, but their models seem to be hit and miss.
Edited by Electrocutor - 9/12/12 at 12:09pm