My favorites:
Martini: Tanqueray or Sapphire (this is a bit pricey though), very dry (pour the gin while looking across the room at a bottle of vermouth
), straight up with a twist (olives=ewww)
Apple Martini: Apple schnapps and vodka.
Chocolate Martini: 1 part creme de cacao, 1 part Godiva chocolate liqueur, 4 parts vodka. Optionally, add a Hershey's kiss.
A gin and tonic or vodka tonic is very refreshing on a hot summer day.
If you're looking for a warm drink, try hot chocolate with a shot of peppermint schnapps, or coffee with Bailey's.