5. 'Saturday Night Fever' (1977)
Few soundtracks have defined a genre; this one did, and more. Released in '77, just as disco reached its populist brilliance/commercial bogus-ness tipping point, it matched proven club hits (the Trammps' "Disco Inferno," Kool and the Gang’s "Open Sesame") with a clutch of Bee Gees songs intended for their own forthcoming album. From "Stayin' Alive" and "More Than a Woman" to KC and the Sunshine Band's "Boogie Shoes," the peaks on this double album can still turn any wedding dancefloor into a seething caldron of joy and embarrassment. The double LP moved over 15 million copies, making it the best-selling soundtrack in history until The Bodyguard stole the title.