Speaking of Crichton, one of my favorites of his is Timeline. I notice it was not mentioned in the earlier responses but I would highly recommend it. Again, book is much, much better than the movie they tried to make.
Currently I am just about done with a book on the Lincoln-Douglas debates. (
http://www.amazon.com/Lincoln-Dougla...5479144&sr=1-1) It has been a very interesting read about a subject I knew very little about.