Well.. I have been on all ends of the scale (save for filthy rich), so I think I can state a nice valid opinion

When I was poor as a rat, I had nothing. I ate rye bread with p-nut butter for a week once, since that was all we had. Was I unhappy? No. Sure I worried about money, but no, I was not unhappy.
When I was rich (ex hubs had a really nice job), I was happy as well. I don't think we lived any differently than we did when we had not even a nickle to bite on, but what we DID do with the money was get some things that made fun even more fun. Things we used, like an open sailing boat. We didn't go out to eat each night, we didn't do extravaganza stuff.. heck.. we didn't even buy more clothes. We were happy that way.
Now I am on the little above poor stage, and I am still happy. I have everything I could ever want, I have a cat who loves me (and the food I give her), I have my basic needs (internet, food, drinks, not in that order, a job, one friend, my dad), and I don't have to turn every nickle over 15 times.
I think it is not the money that makes you happier or less happy (see above, I went through all stages and was happy all along them), it is the estranging part that makes you less happy, and when you have money, I have seen many do this, you buy things you don't need and that don't make a difference. You stay unhappy.
It doesn't buy you friends, it doesn't buy you someone who loves you, and it doesn't buy you happiness at all. Happiness is something that, so I have found, does not have anything to do with money. So, conclusion: money does not make you happier. All it does is make you worry a little less, but happier? No.