I appreciate the thread, as well as your willingness to expose yourself to music that you wouldn't normally think twice about. Am I right about that? Whether or not people respond is another thing, not to mention that the number of metal/hard rock forum members is quite low. I can think of four dudes here with me being one of them. Personally, I would fall into the "hard rock" category as opposed to "heavy metal" which covers a larger variety of bands.
Megadeth is a heavy metal band.
AC/DC is a hard rock band.
Metallica is a heavy metal band but they're the commercial version so I place them in a sort of Def Lepard 'Photograph' type of metal.
I want to say bad things about grunge, but it's not all bad. Soundgarden's Rusty Cage comes to mind. Not that, is a killer tune.