Yes, I have summer on the mind already, so here they are:
* Atlas Shrugged (you could just wait of the movie, but movies are never as good)
* Liberal Fascism
* The Road to Surfdom
All three make a common point that continually fascinates me: They all illustrate how the desire to "do good for others" is the root of totalitarianism. Due largely to these books, I'm naturally skeptical of "do gooders".