Carrie Underwood was named Entertainer of the Year for the second year in a row at the Academy of Country Music Awards Sunday night in Las Vegas, making history as the only woman to win the award twice. She also took home a trophy for her career "triple crown" of ACM honors--entertainer of the year, top female vocalist and top newcomer. Carrie wore four dresses over the course of the night and flaunted her engagement rock, a yellow diamond from fiance Mike Fisher. Taylor Swift was shut out despite five nominations. PHOTOS: WATCH Carrie's acceptance speech: