First of all, this is a world-class city.
If you enjoy New York, Barcelona, Vancouver, London, etc, you will enjoyShanghai. Like San Jose, CA, Shanghai can be very dirty and polluted--the air quality was so poor the day I arrived, I could see what I was breathing--but the beauty of much of the early 20th century architecture, the picturesque nature of some of the older streets juxtaposed against the modern new buildings going up everywhere, the trees along many of the boulevards, the visual pleasure of thousands of people getting around on motorbikes, scooters, motorized bicycles, and bicycles, some with hauling carts attached--is without peer.
(I am staying in the French Concession--the older part of the city--where my friends live, and it is vibrant, great for walking, and very polished/somewhat upscale.)

Second of all, it is a city filled with interesting, motivated young people from all over the world. Native Chinese seem to have thronged here from across China and a strong and growing expat community is quickly coming in as well--there's a feeling of energy and purpose tied to modernization and opportunity that is very compelling.

Finally (and Blogger ate this part of my post), it's a safe and diverse city with low crime and where it seems possible to walk and explore without much danger. Yesterday, we walked around local streets where small shopkeeper's stalls fronted older, derelict buildings, often across from huge construction sites where big new apartment houses were going up, and felt extremely safe and accepted, obvious tourists though we were.
(The only exception to that feeling was at Yuyuan Gardens, where we went to eat Nan Xiang dumplings and I felt like a big wallet designed to be plucked clean (nope, didn't buy anything except an expanded memory card for my camera.)