Now here's a topic I like! Here's my proposal (not an easy pick by any means) :
Warlord - Deliver Us .Warlord are a huge influence on everything under the title "lyrical epic metal".
Manilla Road - "Crystal Logic" Simply put ONE OF THE TOP 5 HEAVY METAL ALBUMS EVER!!!! Absolutely mind blowing musicianship, some of the best and most original guitar leads you'll ever hear, complex and ingenious songwriting, amazing lyrics, simply a MUST buy!
Jag Panzer - "Ample Destruction" This is the album that - along with Liege Lord's "Freedom's rise" - gave birth to what we call U.S. power metal! This along with "4th judgement" and "Age of mastery" are absolute must buys. I watched Panzer live in Greece a few months ago btw, they still RULE!!!
Cirith Ungol - "King of the Dead" I'm too young and ignorant to even begin to judge an album like this! A dark opus in epic metal, a true mystyfying experience! Guitars sharp as razors, walloping bass producing incredible groove, and the screeching vocals of Tim Baker that send old ladies and Euro power gaylords screaming for their lives! And did I mention it's epic as fuck? Plus it's got one of the best covers of all time (Michael Wheelan both rules, and ownz!). THE FINGER OF SCOOOOORN!!!
Now as far as the other bands go, make sure you also get hold of:
Riot - Thundersteel, an opus of american metal.
Dio - Holy Diver, pretty much the same as last in line, his two best solo efforts btw.
Armored Saint - March of the Saint, A.S. are the most american sounding american band ever!!! I know that sounds weird but this is as U.S. metal as it gets, I love them!
Metal Church - St, again patriarchs in U.S. metal.
Anthrax - Fistful of metal, not really my style, but as far as early ballsy u.s. speed goes this is a must
Trouble - "Psalm 9", "The Skull". These two, along with Candlemass "Epicus Doomicus"/"Nightfall" and Scald "Will of the Gods is great power" are the top doom albums ever imo!
Hope I could help, CURSE GOD I WASN'T BORN IN THE 80's OHIO SCENE!!! CURSE HIIIIM!!!
