US here, so there were lots of medals. To be honest, though, I tend to cheer for individual athletes and teams over the nations (maybe I'm just spoiled that way, heh). I'm a sucker for underdog stories, so seeing things like the Sweden women's team take silver in soccer and the Serbian women's basketball team take bronze were really enjoyable, especially in the way they reacted with pure joy. I also like to cheer for my ancestral nations, so I cheer for Norway, Finland, and Great Britain athletes as well.
That being said, I'm a big fan of Phelps, Ledecky and Kim Harrison.