If there is any book at all that magnified my enthusiasm for exoplanetology, then it is The Living Cosmos by Chris Impey. It's mostly on Astrobiology but the parallels to exoplanetology are unmistakable.
An exoplanetologist will learn most from the whole book, but Chapter 6, "Distant Worlds" is what i think is the most devoted to exoplanetology. It's where the planet-hunters are mentioned (such as Geoff Marcy, Debra Fischer and Greg Laughlin) as well as the current techniques used in planet-detection (such as Planetary Transit Method). Future initiatives such as NASA's Terrestrial Planet Finder (TPF) which will be launched in 2015 is mentioned as well.
The book is highly readable, and most of all truly inspiring.