I finally beat Paper Mario: The Thousand-Year Door

[Evil Yoshi Toes]

It's definitely one of my all time favorite Mario games. It's very fun to play and has a very fun story. The cast of characters is especially excellent, some of my favorites being Flavio and Toodles. Even the usual Peach, Bowser and Luigi have a lot of life and personality in them.
And yes I agree, Chapter 3 is really excellent.