I don't get the love for Craven Cottage, I've always found it to be a mish mash of just 25% old interesting bits, 25% lovely setting, but 50% really crap, modern cheap bits bolted on. And it's too small.
I like the Bernabeu, the Emirates, and Wembley. Oh and Lord's if I can have a non-football ground.
In the US (as the OP is there, and he asked!) I really enjoyed Minute Maid Park which I was surprised at because it looks awful from the outside.... very boring, but it's cool inside.
Oh and the Mercedes-Benz Stadium in Atlanta is pretty damn impressive.