In a previous post, I looked at the ONS well-being (or happiness) survey which found that Northern Ireland was the happiest region in the UK. The statisticians at the ONS have done further analysis on their survey by looking at the correlations between an individual's well-being or happiness and various other personal circumstances and characteristics. The study is available here and the Daily Telegraph's coverage is here. Many of their findings are not surprising. Health, employment status, and relationship status all matter for our happiness. Interestingly, given the ongoing debate about redefining marriage, being married has a large effect on well-being / happiness, but having children makes a small contribution to well-being / happiness. Large salaries make a very small contribution to well-being (see the Economist for some evidence which may contradict this).
You can learn more about "happiness economics" from a paper on the topic by Richard Easterlin, the founding father of the discipline, and from the Brookings Institution's website on the topic.