Search google for Smart Shanghai it has pretty much everything with regards to Shanghai nightlife and eating out... it really depends on your age and budget.. the bars Hot_Seller mentioned have pricey western food and at night are usually full of ladyboys and pay-per play girls.
Anything is possible in Shanghai for a good looking guy, plenty of open minded girls who want to party.. Shanghai isnt nicknamed sin city for no reason

Lots of hot taiwanese, japanese and american chinese girls... and the girls who have studied overseas are generally quite open minded !! Hangzhou is also cool place, lots of sweet girls.
Check out the club pics smartshanghai /pictures/ , there are some very wild clubs, but depends on your scene.
If visiting Shanghai i recommend a hotel in Shanghai called the Green Tree Hotel, its around 200 RMB per night, they have a few good locations clean and overall the best deal in town.
Facebook, Youtube etc... are blocked in China so you will need a VPN, i use Astrill which is great and works on iphone too.
If you want to meet local girls online i recommend Badoo, dont fall in love with the first girl you meet.
Most of the guys will look at you with a stare of hate, but physical violence is very rare unless provoked. - If you do get into any type of trouble just run.
As for the pickpockets they are everywhere in crowded places but especially watch out for the eastern european looking Chinese which are from Xinjiang - The women usually carry babies on the front of them to avoid being arrested, i have watched them take phone after phone, everyone knows but nobody does anything about it. - Generally People dont take responsibility unless its for their personal benefit.
People drive insane and take care crossing the road.
People recommend to have the experience of eating cheap street food, bbq meats etc... but i wouldn't recommend it to anyone who seriously values their health. Food scandals are rife in China and using recycled oil from the drains is very common in low end restaurants, old meats full of hormones and fruit and vegetables which have been grown with chemicals like viagra and contraceptive pills. - search google for exploding watermelons.
Eating good can be expensive, my food monthly bill in China is alot more than it is in Europe.
Anything particular your trying to achieve on your trip ?