Tie between Han, Tang and Song. Han, because it was a huge cultural change + lots of political intreague that works as good literature. Tang because of the huge ups and downs, and the whole Chinese renaissance thing. Song is very interesting, but rarely studied and talked about because the Chinese take the latter part of Song as a big patriotic shameful thing. But Song thrived culturally, and did alright for itself early on. There are a lot of hidden gems to find in Song history.

All dynasties. Every dynasty has its own stories.

But Yuan dynasty is was last one that I am interested in.

Qin and Yuan dynasty are my favorite from history, the last dynasty was a mess

The Cultural Revolution is the most glorious and succinct example of "Chineseness" in the whole 5000 years of you know what!