Wine. I almost always bring wine to the appointment unless the provider clearly states she doesn't drink alcohol. Sometimes red, sometimes white, sometimes Champagne if I'm feeling "celebratory".
I chose wine because it's more 'mellow' for me, but there are times I would love a nice Bourbon on ice with a side of 7-Up . Old Charter 12 Year, please!
Scotch, neat, water on the side so I can splash it myself. A decent single malt preferred, but everyone has Johnnie Walker Red. (Or should have, that is.)