[Yuri]

I guess density coupled with a pedestrian friendly design, boosting street activity are the key for a great city. Outgoing inhabitants help as well, as it increase the numbers of amenities available such as bars, restaurants and other equipments.

New York (although their grid doesn't count favourably), São Paulo, Buenos Aires, London, Tokyo are the main examples of that. Smaller cities can do it as well (Porto Alegre, Barcelona, Berlin, etc.).