Not sure where I recently ran across this book, but picked it up - How To Worry Less About Money by John Armstrong.
http://www.amazon.com/How-Worry-Less-About-Money/dp/1447202295It is a good read giving my a slightly different take on this idea of when is enough enough.
"If you have the right attitude, a little money goes a long way; if you have the wrong attitude, even a lot of money won't help you."
