VH1 100 Greatest Artists of Hard Rock

Today, I'm posting the ranking of "VH1 100 Greatest Artists of Hard Rock", (but just the first 20.)There are many bands that I really like in this list. Who do you think the first three must have been?

1.Led Zeppelin
2.Black Sabbath
3.Jimi Hendrix
4.AC/DC
5.Metallica
6.Nirvana
7.Van Halen
8.The Who
9.Guns N' Roses
10.KISS
11.Aerosmith
12.The Sex Pistols
13.Queen
14.Soundgarden
15.Pink Floyd
16.Cream
17.The Ramones
18.Ozzy Osbourne
19.The Clash
20. Alice Cooper