When something inspires me, I can't help but share it with others - to the point where I've felt the need to qualify my recommendations by saying, "I swear I'm not getting paid a commission on this..."!
Here are some of the resources that have inspired me over the years:
Communication
Getting to Yes by Roger Fisher, William Ury & Bruce Patton
Difficult Conversations by Douglas Stone, Bruce Patton & Sheila Heen
Influence: The Psychology of Persuasion by Robert Cialdini
The Trusted Advisor by David H Maister, Charles H Green & Robert M Galford
Leadership
Action Inquiry by Bill Torbert & Associates
The Practice of Adaptive Leadership by Ronald Heifetz, Alexander Grashow & Marty Linsky
Understanding Yourself
Coaching to the Human Soul (Vol 1-3) by Alan Sieler
Drive by Daniel H Pink
The Unopened Gift by Dan Newby & Lucy Núñez
The Language of Emotions by Karla McLaren
Creativity
The Artist's Way by Julia Cameron
Creativity, Inc by Ed Catmull
The War of Art by Steven Pressfield
Personal Transformation
Finding Your Own North Star, by Martha Beck
Passages: Predictable Crises of Adult Life, by Gail Sheehy
The Heroine's Journey, by Maureen Murdock
Inspiration
The Alchemist by Paulo Coelho
Jonathan Livingston Seagull by Richard Bach
"Getting Out of Your Own Way"
I've also created a recommended reading list for the GOOYOW workshop, which you can download here.