>>24580213 (OP)depends what you want from a comic.
Watchmen is genuinely worth a read, but it doesn't do as well if you don't care about superhero stuff generally.
Sandman is kind of a stock answer, and still fun.
Much of Grant Morrison's run on Animal Man and Doom Patrol is also good.
Swamp Thing and Serious House on Serious Earth are from around the same time and also good reads.