Bigfoot Silva was an amazing win, especially since he had just TKO'd Fedor in the first round of the tournament. DC was put in the tourny to replace Overeem and not many people gave him a shot at winning the tourny.
His fight with Barnett was a big eye-opener. Cormier had only 9 fights experience compared to Josh Barnett's 30+ and he had the size disadvantage, but he absolutely dominated him like no one expected.
And say what you will about Dan Henderson, but NO ONE has ever thrown him around like that and he has faced legends from MW-LHW-HW of all different fighting styles.
If I had to pick, I'd say the Barnett win because he was really 2 years into MMA compared to Barnett who has been competing since the early days of MMA