Ozzy Osbourne... what can you say that hasn't been said.  The fact that he's still alive is amazing in itself.   He's smoked, injected and drank just about everything.  He's bit the heads off a bird and possibly a bat.  His first run with Black Sabbath helped form Heavy Metal as we know it today.  Probably the most amazing thing is his ability to stay relevant through several changes in the music landscape.

Here he is in the Glam Metal 80's with "Shot In The Dark" from his 1986 release "The Ultimate Sin"

Here's Ozzy from 2010 with "Scream"

It's fair to say that just about every Metal band for the past 40 years were influenced by Black Sabbath and Ozzy.  Sweden's "Hellfueled" is a perfect example.  Listen to the vocals, if you didn't know better you might think it was the Prince Of Darkness himself.