Personally, I'll take "Singles." Pretty much defined the early '90s, which, being a gentleman currently in his early 30s, happened to be the prototypical "defining era" for my life. But really, phenomenal album in its own right before the grunge movement got too watered down. Old-school Pearl Jam, Alice in Chains, Chris Cornell, Mudhoney, Screaming Trees, Soundgarden, Smashing Pumpkins... all before those guys got their moments of fame. Pretty definitive collection, with the notable lack of Nirvana.
But, I'm an old man now, that's MY classic rock.