As I’ve explained on a few other comments sections in replies to this prompt, I am more a singles person than an album person. But I’d definitely include Actually by Pet Shop Boys for the 1980s and Parklife by Blur or Music for the Jilted Generation by The Prodigy for the 1990s. After that it gets much trickier. Probably something by Muse for the 2000s? Or Girls Aloud? Both brilliant for completely different reasons.