In my first Chinese hostel in Harbin I met a nice and quite knowledgable Chinese woman. She told me many insightful stories about China and about places which would be worth visiting in China.
The following places have been recommended to me by her:
Dalian: Is supposed to be a nice coastal town with very nice and accessible beaches.
Tsingtao (Qingdao): Is a city on the east coast. One of the most famous beers of China is brewed here. It used to be a german colony from 1898 to 1914. However the beaches are supposed to be nicer and more accessible in Dalian.
Jiuzhaigou: Is a Chinese national park with an amazing scenery. Fall, when all the plants are shining in amazing colors, is the best time to visit.
Zhangjiajie: It has the most beautiful, almost surreal scenery (so I heard from several people who have been there). Its supposedly the prototype for the scenery in the famous movie Avatar by James Cameron.
Chengdu: Is a good starting point if you want to see the more Tibetan influenced areas of China which are to the west of Chengdu (5 to 10 hour bus ride). These areas are still outside of Tibet so you don’t need a permit to go there.