ACDC is a hard-rockin' band. They don't stray too much in their songs - you get simple, yet great and heavy guitar riffs, adolescent lyrics (I'm not complaining), and a pretty simple yet up-beat drum beat in every song. You know what you're getting (again, I'm not complaining).
There is one song they did in their "earlier" days with their first lead singer Bon Scott (who died the classic rock-star way - via alcohol and drugs). The song - "It's a Long Way to the Top If You Wanna Rock and Roll" is similar in that it has classic ACDC guitar riffs, BUT they include a bag-pipe towards the middle of the song and it takes it to a whole-new level.
Somehow this song is often forgotten by radio stations who seem to focus on the "standards" like "Back in Black" or "Shook Me All Night Long."