- Simple Heuristics That Make Use Smart by Gigerenzer, et al. (http://www.amazon.com/Simple-Heuristics-That-Make-Smart/dp/0...). I have heard good things about this book but have not read it yet.
- Think Twice by Mauboussin (http://www.amazon.com/Think-Twice-Harnessing-Power-Counterin...)
- Influence by Cialdini (http://www.amazon.com/Influence-Psychology-Persuasion-Busine...)
- You already mentioned Michalko, but his other book, Thinkertoys, is also very good (http://www.amazon.com/Thinkertoys-Handbook-Creative-Thinking...)
- Switch by the Heath brothers is excellent (http://www.amazon.com/Switch-Change-Things-When-Hard/dp/0385...)