There's a lot to be said (and most of it has already) about how well this episode came together, but I was blown away by the actual acting this time around. Jon and Dany in the cave was excellent. Dany on the shore with Tyrion was excellent. Sansa and Arya working through their awkward sibling relationship, and then Arya crushing the fighting scene with Brienne. Meera with Bran and Littlefinger v. Bran. All really, really solid. Plus Davos and Bronn giving some well placed comic relief in bits and pieces.
But all of that paled to Jaime staring down the devastation of his army. It seems like this was the first time you had major protagonists (?) going head to head, and I know I'm supposed to be rooting against the Lannisters, but damn Jamie killed it that whole sequence. I was anxious and terrified right alongside him while Drogan was doing work. I definitely didn't want Bronn to kill the dragon, but I definitely didn't want the dragon to get Jaime either.
They really have done an incredible job bringing his character around 180 degrees from the ******* that pushed Bran out of the tower so he could get away with banging his sister. And Nikolaj Coster-Waldau is absolutely perfect in just about every scene.
Anyway, I thought this was about the most complete episode they've put together. It advanced the plot significantly, covered ground with nearly every character, had excellent pacing and didn't ever feel rushed, was flat out beautiful to look at, and was acted/directed excellently. I think it has to be my favorite of the series.