Is shanghai a must see in China?

I want a cheap priced trip and in the same time I wanted to visit Beijing and Xian because they're a must in China , also I added Guilin due it's amazing scenery and Yangshuo's scenery and Li river. But is shanghai a must see? I wanted only to see the New urban city and it's towers etc. but If I don't have much time and money , Can I escape it? and in the same time I want a 4 stars hotels not 3 so I can't find cheap tours inclufing the four cities , I'd like you to tell me whether it's worth it or not and If you have any cheap tours including the 4 cities , Please leave me it's link

Thanks very Much