I might recommend something like the Coleman Audio M3PH MK2, which is completley passive. It sounds EXACTLY like the audio you have going through it, as it is extremely true to the source.
Check it out,
http://home.dti.net/coley/It would also add input switching as well as speaker switching. Also, the M3PH has left/right mute switches and a mono button to check for phase cancellation.
To my ears, the Coleman line of monitor switchers and controllers are far superior to the Mackie BK, or the pre-sonus central station, with a much wider frequency response, which will allow the depth of your DAW to come through untouched.
Those units may outweigh with more features, but this also means <more electronics in the signal path>
Stay with what works, I guess,
"more signal, less noise"
But as a side note, I would leave my DAW master fader at unity for the best possible idea of what is ACTUALLY going on with the 2-buss. Turning down the master fader before (channel-fader) is all good, but if there is no real reason to turn down the master fader, don’t.
peace
mixwell