1. Crown/Jack & Coke - easy and available everywhere
2. Moscow Mule - trendy but really quite good
3. Whiskey Sour - when I want to be more grown up but without caffeine
4. Caipirinha - see below
5. Irish Cream - good for mixing with hot cocoa or coffee on cold days (tailgating)
Caipirinha is sorta like a Mule, but no copper cup and uses Brasilian sugarcane rum (cachaca) instead of vodka. It also has lime, but coarse raw sugar (cane sugar if possible). Served over ice. The cachaca is pretty strong, and you mix it very strong.
"It warms the cold and cools the heat" or something like that is the phrase.