Check out High 'N' Dry from Def Leppard. Seriously, this is one of my favorite hard rock albums. Before Def Leppard succumbed to fame and pop/rock stardom, they rocked pretty hard.
Black Sabbath with Ozzy or Dio, if you want metal, check out "Dehumanizer"...it is like nothing you've heard before with Dio. If you're a fan of the game DOOM, you'll probably recognize "After All The Dead".
If you can, check out King Diamond. His vocals can be quite annoying, but the music is great; and all of his albums revolve around a story. If Edgar Allan Poe was in a metal band, he'd be in King Diamond. As for albums, check out "Abigail", "Them", and "Conspiracy"
Mercyful Fate is one I like too; it was King Diamond's band before his solo band. More along the lines of Judas Priest/Iron Maiden, but their lyrical content might turn you off. They were one of the first black metal bands, and talked a lot about the occult, Satanism, etc., so that might turn you away. They were a great influence on Metallica.
Try Motorhead. Just some simple rock 'n' roll, but they are one of Metallica's biggest influences. All I have to say is they've got Lemmy. Check out "Ace of Spades" for a good starting point for the band.