There's a good article about happiness in The New Yorker, and it's online here.

I think a lot about happiness. That's pretty much the whole subtext of my Bridge novel -- how to be happy, or cope with the impossibility of being happy. So the article felt especially apropos when I read it today on my lunch break. I've got an old half-written novelette I might finish someday, called "Antiquities and Tangibles", about a woman who finds a little magic shop and tells the smug proprietor she'd like to buy happiness. Not a love potion, not a magic ring, not a flying carpet -- just happiness. Which the proprietor considers a pretty difficult order, but he gives it a try. I could never find a decent ending for the story, though I still think about it from time to time.

The article even has an equation for happiness: H=S+C+V. Happiness equels your "Set Point" (genetically determined baseline happiness) plus the condition of your life (are you starving? do you have shelter? do you have companionship?) plus your voluntary activities (the things you do for love). Makes sense to me. It's the fact that S is a constant (albeit one that varies from person to person) that makes things difficult, and why being rich and famous and popular is no guarantee for happiness at all.

The article also introduced me to the phrase "hedonic tradmill," which is one of the best phrases ever.