First, a good reference site:
http://www.drinksmixer.com/
Second, a couple of drinks:
Vodkist: this is something my friends and I created and decided we liked more than screwdrivers; basically use sunkist instead of orange juice for the screw driver, gives it a different flavor, but if you're making strong drinks (or drinks for girls who don't like alcohol-tasting drinks) it generally masks the flavor of the vodka a little more.
Martini: I saw someone else had posted a recipe for a martini, but there are dozens of variants; I go for a drier martini, 10 to 1 gin to dry vermouth, shaken with ice and an olive in a mixer then strained, toothpick the olive and add to the drink. For the love of god use good gin too (bombay sapphire is mine) :P Other variants involve the vodka martini, sweet martini (sweet vermouth instead of dry), twisted (twist of lemon or lime), dirty (dash of olive juice from the jar), and many others.