Why do some people enjoy life and others don't? - this is the convention my girlfriend has just gone off to, which sounded really interesting. Would have liked to have gone. Ah well :)
One thing though. Seligman seems to concentrate on a very much desire-driven approach to happiness, e.g. exploiting our strengths - good advice, but (IMHO) somewhat contradictory to the teachings of both the Tao Te Ching, and Zarathustra, and I'm sure many others. Their teachings seem to revolve more around, to one extent or another, being content with what you have, and indeed taking pleasure in having less, depending on less. The difference seems to be that we should aim under ourselves in order to achieve more peace and happiness.