I'm rather fond of The Great Darkness Saga, which was a run of LSH back in the early 80s. Very cool stuff. Darkseid shows up, amasses a bunch of power, and mind controls all the Daxamites to go conquer the universe for them . Prettyy much everybody who's anybody in the 30th century shows up to oppose him.
Of course the Watchmen would need to be mentioned. Then there's "The Last Days of the Man of Tommorow" which was written by Alan Moore as a send off to the silver age superman.
buzzard