I very much enjoyed Bryan Peterson's teaching style, in which he juxtaposes a typical snapshot and a good composition of the same subject. In the text, he explains the thinking process or technique that led him from the former to the latter. It's terrific to see dozens of examples of how a simple change of viewpoint or camera setting can make a huge difference in the quality of the resulting photograph. Of the many photography books I've read in the last couple of years, this is the most inspiring, and it's both extremely approachable and immediately applicable.