This battle was better than all the others because it was such a complete surprise. Think about it-- we knew Blackwater was coming, we know Castle Black was coming, there were a couple that we expected, but didn't happen or weren't shown-- but until that ominous mist started to roll in, there was no hint that it would go down.

Also, the Lord of Bones getting lulstomped was completely unexpected as well, and a great surprise ending to a supposed bad ass.