I came across this paper while working on the second last subject for my MBA (Organizational Behaviour, yay!):
Sachau, D (2007) Resurrecting the Motivation-Hygiene Theory: Herzberg and the
Positive Psychology Movement. Human Resource Development Review 6 14, 377-393.
The paper, from p386 on, provides a good review of the scientific basis of the phenomenon of hedonic adaptation (aka "escalating zero point" for dissatisfier factors such as not having enough money/comfort). For any crazy people like me who like to know that a theory is backed up with actual evidence, it's a really interesting read. You might be able to find it for free on the internet, or certainly if you have access to any university libraries and all their subscriptions.
Not everyone's cup of tea, I know, but provides a nice foundation for discussion with any scientific types ;)