If at the lounge, port (they only have a beer/wine license).
If at home, bourbon (Woodford, Knob Creek, Blanton's, or whatever I have at the time) or Trader Joe's blended Scotch.
Some times water, or nothing at all. My drink choice habit was driven by smoking cigars, which I find the hard alcohol really helps to clean the palate, and is almost necessary with cigars. Much less of an issue with the pipe
I don't smoke in the morning, and can't do coffee at night, so.....