Ramones,Rocket to Russia, and Road to Ruin are generally considered their best albums.
While their mid-to-late 80s output is a little hit or miss, everyone likes 1984's Too Tough To Die.
It's Alive! A candidate for one of the best live albums ever, it's the original lineup in London, England, just tearing it up for nearly an hour. It set a trend for later (and, notably, faster) live albums in that most of the time, as soon as one song would end, Deedee would immediately shout "ONETWOTHREEFOUR!!!" and they'd go right into another one without so much as catching their breath.