Good question!
We do play music at a low volume and try to gear it towards the audience. The stereo is in our reception room is which next to the dining room, so its usually barely audible.
If its during opera season and the house is full of guests who are attending our world class opera house, then the playlist of heavy metal and Nirvana gets skipped. Our own musical tastes are as eclectic as our home is, so it gets interesting.
Being close to tons of outdoor recreation areas, we get many more younger, very active folks and when I see them wince when the classical comes on, I usually can tell I loaded the wrong CD.
Our place is very informal, unpretentious and appeals to all ages and interests, so its really fun for me to fire up itunes and make some nice CD mixes on the spur of the moment.
In fact, if we really connect musically with a guest and they liked what they heard one day or ask about something they heard while here, I'll have a copy burned ready for them as a parting gift when we hand them their reciept at check out. We even allow guests to take CDs with them on their daytrips if they left the ipod at home or didn't pack any music.
That gesture has been greatly appreciated many times and not a lot of effort to do so.