What should I be sure to see in China? (traveling in December to Beijing, Guilin, Xian, Shanghai)?

And any other smaller cities / towns in between. I will be traveling with someone fluent in Chinese.
I will be traveling around China in the month of December and am currently planning to stop at Shanghai, Xian, Guilin, and Beijing. I will be traveling with someone fluent in Chinese.

Where are you from?I think you will visit Shanghai in December.Of course, other cities are good,too.

hi,sounds great...i think Shanghai is a modern city while Guilin is a fairyland and Xian is a historic city...i have found some introduction of these cities..
http://wikitravel.org/en/Shanghai
http://www.foreignercn.com/index.php/action_viewnews_itemid_16130.html
http://www.foreignercn.com/index.php/action_viewnews_itemid_6489.html
i like Guilin most cause of its scenery is so amazing,the nature reserve is located at the source of the Lijiang River with a total area exceeding 17,000 hectares. With a history of over 2,000 years, the area is renowned for its green mountains, clear water, and uncommon stone formation. As for its unique geological position and biodiversity, the reserve has been selected as one of China's 16 key areas with internationally significant land diversities...

Try to see everything that you look at.

and dont forget yunnan province.
chengdu,sichuan,guizhou,these are good places too!

Hong Kong, Hanzhou and best of all hainan, its totally like the hawaii of china!

In Guilin, you definitely should take a boat trip down the Li. It is a spectacular view and they usually serve a lunch directly from the river. Quite fun.

Also, go out at night in Guilin. The night market is quite a spectacle. Very close is a bar district with (I kid you not) some good Irish bars. If you do go out, forget the car cabs, take a motorcycle one. 2 RMB and the ride of your life.