The Whiskey Sour is an old classic.
Here's the recipe:
2 or 3 ounces whiskey
2 tablespoons lemon juice
1/2 or 1 teaspoon superfine sugar
3 or 4 ice cubes
1 orange or lemon slice or peel
Pour all the ingredients in a cocktail shaker and shake heartily. Strain into a Delmonico glass (if you have it--it's like a diner's juice glass) and garnish with orange or lemon and toss in a maraschino cherry.