What is the greatest city in the world in your opinion?

Jeese...it is so hard to say. On your list I have been to New York, London, Paris, Dubai, Rome, Venice and Hong Kong. I did not like Dubai at all. It is WAAAY too hot and you have to be indoors. If you like shopping, recycled air and sightseeing through windows then that is your city. I absolutely love New York. It is in a whole different category. I just love it! Out of London, Paris and Rome I would say Paris. There is just so much variety. Every district is different and the city itself is an attraction. I like London too, but not as much as Paris. Venice can't really be compared. It is an incredible sight...fabulous but to put it in the same category as New York and the others is no comparison. Two cities that you haven't mentioned but are on my tops list is San Francisco. It is an incredible city. Well laid out, clean, easy to get around and lots to see. Another is Krakow, Poland. This city has so much history from Medieval, WW2 (Holocaust), Cold War etc. and today it is just a genuine city. I also love Miami too.

Teroy, I have been to every city on your list and here are a few more, just for the mix. Sydney, Australia, Singapore, Amsterdam and anywhere in New Zealand!! In the US, I would add Chicago and San Francisco to your choices. Everyone defines the greatness of a city based on their personal criteria. My recommendation would be to start broad with your on-line research and narrow it down, based on what you want to see and do when visiting a city. Don't forget to research how friendly the different cities are, its crime statistics, mass transit, etc.....

Good Luck...