Answer:
Music and Literature
Given the length of time that Britain has been around, which is far longer than the United States, they certainly have a much more substantial list of celebrated writers and artists. While the U.S. can proudly offer up writers such as Faulkner, Hemingway, and Flannery O'Connor, Britain has Shakespeare, the famous poet and playwright from the 16th century. As far as most literary scholars are concerned, Shakespeare trumps all.
When it comes to music, classical excluded, the United States probably takes the cake. The blues, which originated in the Mississippi Delta, has influenced nearly every known rock and roll icon, both British and American. Even though Britain can claim Led Zeppelin and The Rolling Stones, both of them have credited American music style as their inspiration. Oh, The Beatles, you say? America has Elvis.