You have to love a band who spent 5 years playing 3 hour sets a night, released 6 albums and were finally discovered playing a birthday party at a
Mexican Disco .They deserve Rock God Status, not to mention brought one if not the best guitarist into the world for all of us to admire.
70's it would be deep purple altrough i like ac/dc more they just arent as metallic
80-84 it would be metallica. Very good albums but they didnt invent thrash metal. Overkill did that a few years before them.
85-90 it would be megadeth. Thrash metal at its best. Good heavy riffing and good solo's.
90-96 it would be Death. Very technical, progressive and just plain good. Despite the gore suggesting title this band most likely has more depth in
the lyrics in this period than about 95% of all metal bands.
96-06. Opeth. Hands down. They brought metal to a level thats just beyond everything. The only band i know with very sudden speed changes. From slow
acoustic to Death metal riffing in a instant. Uniquely done. No other band mixes acoustic guitar with electric guitar like they do. It has been said
that they are the most innovative band since pink floyd.
There are a few of my favorites which didnt make this list but are still very good.
Kyuss the inventors of Stoner metal
Moonsorrow the masters of viking metal
Isis best of the athmospheric sludge bands