Rolling Stone Magazine: Best Metal Album!

Some time ago, Rolling Stone magazine asked its readers to vote for the best Heavy Metal album of all times! As usual the results were kind of weird.
 I believe that all these on-line polls are most of the times crap, but I'm having fun reading them.
So here's is the list of the Top-10 Heavy Metal albums of all times, according to the readers of Rolling Stone magazine:

01. Metallica - Master Of Puppets
02. Black Sabbath - Paranoid
03. Black Sabbath - Black Sabbath
04: Iron Maiden - The Number Of The Beast
05. Metallica - ...And Justice For All
06. Slayer - Reign In Blood
07. Guns N' Roses - Appetite For Destruction
08. Metallica - Black Album
09. Led Zeppelin - Led Zeppelin II
10. Metallica - Ride The Lightning

  I will not write my opinion about this list at the moment, but I have one question: What is Led Zeppelin doing among Metallica, Slayer, Guns n' Roses etc? I really can't understand!
And I'm sorry, but where is 'Sad Wings of Destiny'? (Judas Priest). And that's just the first album that came to my mind when I saw the list.
Anyway, I just posted here for you to see and you can judge by yourselves...
Have a nice day! :)