I would like to direct you to the study by Dan Gilbert that concluded that a year after either winning the lottery or being paraplegic, the levels of happiness of people were about the same.

http://zionsphere.hubpages.com/hub/perceptionofhappiness

Unfortunately, I could not find the original study, however that link seems to summarize it pretty reasonably.

While most people may choose the money, that choice isn't necessarily better, and hence doesn't mean the people with more money are necessarily 'happier'.