19. Megadeth, 'Rust in Peace' (1990)
No other band from thrash's first wave combined airtight songwriting with sheer instrumental mayhem as creatively or skillfully as Megadeth did on Rust in Peace. From the rapid-fire descending lick that kicks off two-part opener "Holy Wars ... the Punishment Due" to the final staccato rhythmic churn of "Rust in Peace ... Polaris," the album is a breathless 40 minutes of Dave Mustaine's finger-twisting, labyrinthine riffage (check out "Poison Was the Cure" for just one of many bonkers examples), snarling war-and-religion obsessed lyrics – "It was a time in the world when the Cold War was still a real issue; we were pointing toward the East with our nukes out," the singer has said – and neck-snapping, shift-on-a-dime arrangements, all of it delivered with fierce, punkish intensity and an unusually nimble rhythmic swing. Rust also marked the debut of soon-to-be-christened guitar hero Marty Friedman, whose technically adroit, exotic-scale-tinged leads served as an ideal foil for Mustaine's ripping, New Wave of British Heavy Metal–style shred, as exemplified by the pyrotechnic six-string tradeoffs that highlight UFO-conspiracy-themed classic "Hangar 18." Megadeth went on to greater commercial success in the next few years, but Rust still stands as the thrash summit all chops-crazed followers aspire to scale. R.B.