The 80s was full of great heavy metal music, and I don't mean hair metal, despite some of those bands being pretty good though. A lot of metal was underground and didn't reach as much commercial success, so it might've not necessarily "saved" the decade, but if you're into that type of thing, it's the golden age of such music...
Most bands/artists people have mentioned are good examples of great 80s music. I don't have much else to add.
Asia
A prog supergroup, at least early on.