In the winter it's mostly Scotch. Single malt Scotch whiskys for the most part, and even more specifically, the really smoky ones from the Islay region. I also like bourbon too, occasionally.
In the summer I like margaritas, gin and tonic, and caipirinha.
Other favorite mixed drinks/cocktails that I tend to order as an aperitif before a formal dinner, are sazerac, old fashioned, kir, kir royale, and the French 75.