One book that has been on my to-read list for a while now is http://en.wikipedia.org/wiki/The_Forever_WarThe Forever War. I recently finished Starship Troopers again, and I thought that I'd go with a military novel on the opposite end of the spectrum. Regarding the class, I thought that it might make a good counterpoint to Starship Troopers (although like I said, I haven't read it yet) and could prompt some good class discussion and cross referencing. Another Heinlein book which deserves attention is The Moon is a Harsh Mistress. Not sure if its the right length for your class, but it's a gripping read and I think Heinlein's best work. Also, I'll shout out perhaps my favorite book - Snow Crash. If I were looking for a reason to justify puting it in a class, I would say its an archetype of the distopian libertarian future, but the truth is its just a really fun read.