How the hell did I miss that one? Probably the harshest, heaviest power ballad ever.
Another hard hitter: Rene Didn’t Do It (Russ Ballard)
Heavy? Hard to top Heep’s “Pilgrim”. Strong intro, great bridge, and then they finally just run you over like a tank...
Another memorable intro is Ozzy’s “Crazy Train”, although I read somewhere that Sharon Osbourne ripped off Lee Kerslake and Bob Daisley for the credits on that one.
When it comes to more melodic, Prelude 12 / Suite Madame Blue (Styx) IMO deserves honorable mention for its intro, too.