"Fooled By Randomness" by Taleb is one of my favourite books of all time! I found it really eye-opening.

I'm currently reading "Outliers" by Gladwell, and it's a great read! I'll probably try and pick up a copy of his "Tipping point" next.

Another good psychology/behaviour/economics book is "Freakonomics", and it's sequel "SuperFreakonomics". Both interesting reads. If you haven't read "Fooled by randomness" yet though I'd definitely recommend that first!