I've posted about various studies that show that money and happiness aren't linked. Here's an article on the Motley Fool site pointing to a study that found that people who focused primarily on money (or prestige, or "success") were actually more likely to be unhappy.
Unfortunately, it doesn't name the study in question, but here's what the article has to say:
On the other hand, a survey of 800 college alumni showed that classmates who valued high income, job success, and prestige more than close friends and love were twice as likely to be "fairly" or "very" unhappy.
Happy people, it seems, concentrate on their own successes and don't compare themselves -- their income, their family time -- with others. They do not judge others or dwell on negative feelings. If they do dwell on the better performance of a colleague or friend, it is to learn ways for self-improvement.