Here a few ways to spend you ten days. The numbers in quotes are days to spend including transportation time in and out. Flying is recommended. I skipped the attraction details so you'll have to research a little on your own or ask more specific questions regarding each attraction.
1. If you are never visiting China again after this:
Hong Kong (2), Hangzhou (2), Shanghai (1), Beijing(3), Xian(2)
2. If you like nature:
Hong Kong (2, the sea), Guilin (4, the lake), Huangshan(4, the mountain)
3. If you like culture:
Hong Kong (3), Shanghai (2), Suzhou (1, Day trip from Shanghai), Zhouzhuang (1, Day trip from Shanghai), Hangzhou (3)
4. If you like food:
Hong Kong (5), Canton/Guangdong (5)
5. If you like shopping:
Hong Kong (5), Shanghai (5)
6. If you like exotic animals and plants:
Hong Kong (1), Xishuangbanna (5), Jiuzhaigou (4)
7. If you like camel riding and Buddhism:
Hong Kong (1), Dunhuang Silk Road ride (9, it’s normally a 12 day trip but you don’t have to go all the way.)
8. If you like Kung Fu:
Hong Kong (5), Shanghai (3), Songshan/Shaolin Temple (2)