Depending on the house, I select either light Jazz, Swing Era/Big Bands (think Sinatra) or light Classical. Never rock and roll, never loud Jazz and NEVER anything that overpowers the mood or the house. The music should be subtly additive to the vibe of the house.
Recently, I had an open house attendee come in and, upon noting the music, mentioned that she didn’t think her agent “got it”. Her house is on the market too and when she returned home after an open house, the agent was playing loud rock music that he liked, but it was a total distraction instead of an “additive vibe”. Needless to say, she wasn’t happy.
If your house is on the market, have the TV set up to play music during your open houses. The music should make potential buyers feel welcome and relaxed. Ask your agent to keep the TV on that station during the open house. You’ll be surprised how much it it sets the tone and relaxes buyers while they are in your home.