> However, they are not more likely to be happy (down to a certain point - earning less that 70K affects your happiness; above that though, it doesn't seem to have an influence).
I thought that was a misinterpretation of the data, which showed essentially logarithmic growth of happiness with respect to money? When plotted on a linear graph, the curve seems to go flat after a certain income level, but it actually keeps on increasing. Which would mean that more money results in more happiness, but with diminishing returns.
True, but OP mentioned fun.
It's also true that more wealth doesn't seem to make me happier, in and of itself. It does mean I have much less stress. That makes me more content, which some might call happiness.
Happiness != Fun. Sadly, we often seem to try to maximize Fun (/pleasure/ease/etc.), and not Happiness.