It's a big week for soda ads. Tonight, during "American Idol," Diet Coke will unveil its first commercial featuring Taylor Swift, shot in her hometown in Nashville. The spot by Droga5 shows the singer writing out the words to her new track, "22," interspersed with shots of other people rocking along to the song. It comes right on the heels of Beyonce's turn for Pepsi. Which ad do you like better? Vote over on AdAge.com.