6) Double Star by Robert Heinlein. Read it on my Palm Pilot thanks to getting the electronic version at Fictionwise. Of course it's The Prisoner of Zenda with spaceships, but I was interested to notice just how much of the plot was subsequently ripped off for the Kevin Kline/Sigourney Weaver movie Dave. Also his choice of the Dutch royal family as supreme rulers of the solar system gave me some private amusement given my own occasional contacts with the real Dutch royals. But what really grabbed me was Heinlein's effortless portrayal of grand political ideas, and indeed an election campaign, as background material to the main story. Compare with Philip K Dick's Cantata 140 which I recently reviewed for Infinity Plus, with one of the least realistically portrayed election campaigns I have ever encountered in literature. A very good read and worthy Hugo winner.