A lot of places a can be seen as a tourist trap. But usually you need to use your smarts and avoid the trap part and try and see the attraction part of it. If you travel to these places during national holidays, they will be full of domestic tourists. Keep this in mind.

The wall and terracotta warriors fall into your category but are simply a wonder.

Happy travels

Well if you take any type of tour bus, then they will be making multiple stops at real tourist traps.... tea houses, jade places, TCM doctors, etc... 

As far as not worth visiting... any zoo... you'll either be let down from the lack of animals or pissed off for their living conditions.

All the Beijing hotspots (the Great Wall, Summer Palace, Forbidden City, etc) during the Nat'l holiday. I had a friend say it was the worst experience ever because of the ridiculous number of people packed side by side.

Forbidden City was tiring, not in a physically exhausting way but simply, plain out boring as hell! Just went there last week. Stay away from that place, nothing to see there.