If there's one book that you read...

At the risk of sounding a bit doctrinaire, I strongly suggest that you read Stumbling upon Happiness by Daniel Gilbert, a professor of psychology at Harvard. This is not a self-help book, but instead is a remarkably witty and erudite book complete with lots of studies and evidence that will explain why human beings are so bad at choosing what makes them happy and what you can do to change that. Please read it, and here's a link to a 20 minute talk by Gilbert to whet your appetite.Publish

One of Gilbert's points -- and what Buddhist monks have long known -- is that beyond a certain minimum money doesn't really bring one happiness, but the belief that money = happiness has to be present ( in spite of it being untrue) for the world's economy to survive.