I don’t remember really where I got the question last but I get it a lot and the answer has previously always been buy a Roundtable…

Well as of today I will change that answer.

Its called The INTERACT AT-OC from ClearOne

Add your conferencing room to the Communications Server Ecosystem with the INTERACT AT-OC . The INTERACT AT-OC is a complete room audio solution that connects to the Microsoft Communications Client’s PC with US B audio. It includes a tabletop dialer, an audio mixer, loudspeakers and microphones. Simply unpack the solution, plug in the microphones, connect the loudspeakers, add the PC and the room is ready for a CSCS conference.

• Applications
  Use Collaboration capabilities in the group room
  Video conferencing
  Web conferencing
  Audio Conferencing
  Enable Microsoft Communications Server in group rooms
  Boardroom
  Training Center
  Executive Office
• Advantages
  Bring Microsoft Communications Server Voice into the Conference Room
  Just add a PC to run the Communications Server
  The PC connects to INTERACT AT-OC via USB
  Create Group Video Conferencing using Microsoft Communications Server at a fraction of the cost
  Just add the PC, LCD and USB Camera to INTERACT AT-OC.
  HD capabilities with Communications Server
  As easy to install as a Conferencing Phone
  Plug & Play
  Connect Microphones to Mixer
  Connect Speakers to Mixer
  Connect Dialer to Mixer
  Connect PC to USB Port
  No programming required
  Uses Desktop Microsoft Communicator Client

More info http://www.clearone.com/docs/datasheets/800-154-002-02-DS_Rev1.0_INTERACT_AT-OC_Datasheet.pdf