Off the top of my head, of the places I've played -- which is a big caveat, having never played MPCC, LACC, Olympia Fields, Baltusrol, or some others -- and assuming we're talking about only private clubs, my U.S. rankings would be:
Winged Foot: two great courses; some think the East is almost the equal of the West; membership is somewhat indifferent to the course they're playing.
Olympic: Having a terrific par 3 course on the cliffs of the Pacific beats out the others below.
Merion: 2nd course is weaker than WF East
Congressional: I think the Blue is a little underrated (in part because of conditioning issues), and with the renovation, the Gold is a solid course.
Saucon Valley: haven't played the renovated Old; the others are a little outdated IMHO.
Berkeley Hall: only played one of the courses, but the one I did play wasn't all that memorable.