Wireless Speakers?

If it's bluetooth, don't. Any interference sounds a lot like the speaker is blown.

Tried something like this using for the computer using a Logitech bluetooth receiver, a Lepai 2020 ($25) and JBL Loft30's. Ended up plugging into the headphone jack of the computer almost immediately.

Haven't tried something like the SONOS, which are ethernet based. However, ethernet works in packets and not really designed for synchronous analog signals.

There are wireless DAC's that work better but that gets more expensive and may only work with certain software.

I've read favorable opinions of the Dynaudio Xeo series. For a den, probably the Xeo 3 would be more appropriate.

While I haven't heard the Xeo's, I do own other Dynaudio standmount speakers and they sound balanced and accurate.

Here's a link:

http://www.dynaudio.com/int/home_loudspeaker_systems/xeo/xeo3.php

Sonos can be very good. You need wifi or Ethernet to make it fly. Just hang a Sonos Bridge ($50) off your router and get a Connect unit for $350. At that point, you can use the solid DAC in the Connect, or go dig out to the DAC of your choice. Add an amp and speakers (as much or little as you want to spend) and you're good to go.

Control the system via a free iPad or iPhone app.

You can stream from a remote networked library on hard disk or from an on-line service, and/or hang a cd player off the connect as an in-room source.

SQ can be very good (especially with an external DAC) and is mostly limited by the quality of the DAC/amp/speaker you've chosen. Moreover, the system can be expanded to as many rooms as you like. The downside is no ability to handle HD files and a bill that mounts quickly as you add rooms. Notwithstanding cost, I was an early adopter of the system and I'm now at 11 (I believe) rooms on the system.

Good luck

Marty