My 80's favorite tones - strictly from guitar tone only, ones that I found to be great regardless of genre.
1980 - Angus and Malcolm Young on "Back in Black" - a mix of several 50w and up Marshall's as Tony Platt was kind enough to give some details of in this
great thread about the production of "Back in Black" along with stuff from Terry Manning. I think it is and always will be THE tone of straight out Rock n' Roll.
1982 - Accept's "Balls to the Wall" - great songs and great tone. Michael Wagener did a great job on the production of this album and provided a great base for the dual guitar riffing of Wolf Hoffmann and Herman Frank. Just dialing in a similar tone gets my head a bobbing.
1984 - Alex Lifeson's "Grace Under Pressure" (especially on the Grace tour video) tones. Pure solid state, heavily processed sounds, but just so tasty. Also one of the most difficult to nail sounds simply because of the amount of processing he was playing around at that time. Chorus upon chorus, muli-layered delays, compression, active single coil pickups and those beautiful super-strat Signature Aurora guitars.
1986 - "Epicus Doomicus Metallicus" by Candlemass. One word - crushing! Doom the way doom should be. Great dark and brooding tone that just crushes you when the slowed down riffing begins.
1990 - Eric Johnson's tone on "Ah Via Musicom". The man after the worlds most perfect tone (if you've never read about his obsession with tone than you really should) created such a wonderful sound on this album. A guitarists guitar album that also crossed over into the mainstream. With songs like "Cliffs of Dover" and "Rightous" - just great great tone all over this album.
My choices are not really that metal (well some of them), but then again I'm more impressed with great lower gain tones than I am over gained ones.
As always your mileage may vary.