For the PCT, try "A Blistered Kind of Love". It's written by a young couple who hiked together.
For general ideas, I agree with Doug that Beyond Backpacking is great. Take some of the advice with a grain of salt, but Ray is inspiring and creative, if controversial.
For trail info, try Hiking The Triple Crown. This book gives an overview of the AT, PCT and CDT, and also gives a good overview of thru hiking jargon and tecehniques.
I didn't care for A Walk in the Woods much. I thought it exagerated the hike and although funny, it didn't represent much about the best aspects of a long hike.