This is a big question, one which I am probably not qualified to answer in any sort of official way, but it’s interesting to think about anyways.
I think it’s fair to say that if you are in a constant state of financial worry, you’ll find it hard to be happy. But there are also very wealthy people who aren’t happy either. So clearly money doesn’t buy happiness the same way it buys a pair of shoes or a loaf of bread. But money can buy peace of mind and fun, which are important to happiness. Money can make your day to day life easier, less stressful and more enjoyable, all of which contribute to happiness. Money can’t buy friends or family, though, which are, according to some psychologists, the most important factor defining happiness.
I think it depends on how you spend your money, whether or not it buys some happiness. Many studies have shown that people who spend on experiences tend to be happier than people who spend on things. So if you buy a nice meal with a loved one you’ll be happier than if you bought another pair of shoes. Or if you spend your money of scuba diving lessons and then go to Cozumel you’ll be happier than if you buy every twelve laptops. And of course this is very dependent on the individual. A techie might like the twelve laptops better than the trip to Cozumel. But in general, buying lots of things will only lead to clutter and stress about mess while buying experiences leads to fun and great memories.
So I guess my take on it is that money can sort of buy happiness. It can at least by spent in a way that will contribute to your happiness, rather than taking away from it.