I've read all but Roadside Picnic on the 20th century list. I cannot agree that Ender's Game, Hyperion and 1984 deserve to be there. I've only read about half the list for 21st century SF. But The Windup Girl is definitely overrated. Of the 21st century fantasy I've only read a couple of Gaiman's, Fforde and Clarke. The City and the City making both SF and fantasy lists is not a good sign, although finding it impossible to believe in the narrator in Embassytown was worse. Is China Mieville really any good? Putting Animal Farm on the list is an indictment of the Locus community. PS These lists didn't transfer neatly, so here's a link: http://www.locusmag.com/2012/AllCenturyPollsResults.html
Have to agree with 1984 not deserving to be there, it was important to bring that particular subject to the public consciousness. But others wrote on the some subject and did it better. I've never been impressed with Orwell's writing style. On the up side of the list, can't argue with the novel in the number one position for 20th century science fiction, Dune (imho) is the single best SF novel ever written.