1984 is good good, thought not as grand as animal farm imho. Brave New World is also excellent.
Dune isn't so bad. I didn't like it the first time through; rereading it made me appreciate the book a little more. I still complain that, for having no characters with whom we are supposed to associate, it screws the political intrigue with the right/wrong notions pervading the book, but that's just me.