I've become accustomed to a glass or two of my wife's red wine at the end of the night. It's a sweet shiraz called, I kid you not, 'Jam Jar'. It's inexpensive and almost like drinking liquid Smucker's... but, d*mn, does it kick like a mule. a couple (abundantly full) glasses, and I can settle back in my Zero-G and drift to sleep.
But, normally, I'll just take a tall Rum&Zero, no ice. (2 jiggers Morgan's Spiced + full can of Coke Zero... essentially 3x normal Rum&Zero, in one glass)
If I'm out and want to nurse something for the evening, I'll get a Disaronno on the rocks to sip at. (Liquid marzipan... I mean, really, what could be better?)