One of the radio stations that I listen to (and Wendy abhors), had people vote in for the top classic rock bands of all time. Their list consists of 93.1 bands, but the top five were:

1. Beatles
2. Led Zeppelin
3. Rolling Stones
4. Eagles
5. Aerosmith

My own all-time favorites are:

1. Beatles
2. Steely Dan
3. Fleetwood Mac
4. U2 (if it genuinely counts)
5. Creedance Clearwater Revival