Wikipedia has some opinions on the configuration of rock bands…
The four-piece band is the most common configuration in rock and pop music. Before the development of the electronic keyboard, the configuration was typically two guitarists a lead guitarist and a rhythm guitarist, with one of them singing lead vocals, a bassist, and a drummer e.g. The Beatles, KISS, Jackyl, Foo Fighters, Metallica, The Clash, Creedence Clearwater Revival, The Kinks, The Fray, Sonic Youth, The Smashing Pumpkins, Arctic Monkeys, Franz Ferdinand. This is popular with bands for its versatility.
Another common formation was a vocalist, electric guitarist, bass guitarist, and a drummer e.g.The Who, Led Zeppelin, Queen, The Ramones, Sex Pistols, Red Hot Chili Peppers, R.E.M., Blur, The Smiths, Echo and the Bunnymen, The Stone Roses, Creed, Black Sabbath, Van Halen, Rage Against the Machine, Gym Class Heroes, The Stooges, Joy Division, and U2. Instrumentally, these bands can be considered as trios. This format is popular with new bands, as there are only two instruments that need tuning, the melody and chords formula prevalent with their material is easy to learn, four members are commonplace to work with, the roles are clearly defined and generally are: instrumental melody line, rhythm section which plays the chords and/or countermelody, and vocals on top.