I really believe every city is the same in general. The idea that one place is better to live than another is somewhat sad. If one can't be happy in one place, what makes one think they will be happy in another?
Will more clubs, pretty buildings, restaurants and downtown parking make happier people? I guess some, but I wouldn't consider it lasting.
As for the best city in the world? Well that is easy, it is where I live of course!
I think in a lot of ways you are right Brendan, particularly when it comes to well developed Western cities. But I do think some are definitely better than others. For instance, at the other end of the spectrum are cities like Lagos. In my understanding, most westerners there have full time guards at their houses. Going outside is dangerous due to the many muggings and serious police corruption. I think it would classify as a 'worse' place to live. To me the most important criteria are; a sense of security, parks/open spaces and restaurants/cafes. One major disadvantage that Melbourne has is the difficulty in visiting other parts of the world - it's just too far away! European capitals have a lot going for them for that reason.