The Contemporary is my favorite resort and its concourse I feel defines the hotel more so than the lobby. The Poly however has the best, most definative storytelling lobby.
The Contemporary's Grand Canyon Consourse (Even though it lost that theming long ago) is the best - Nothing beats cavernous feel it has and the monorail... And the renovation is going to do wonders!
I have to go against the crowd and vote for The Boardwalk Inn! It's just awesome how that place takes you back to the shore. The penny movie players, music, and huge furniture really kicks some backside in my opinion!
I also have to throw in with the WL. I'm a sucker for the stone fireplaces and the overall woodsy feel of the lobby. Just walking into the lobby automatically relaxes me.
I agree that the WL and AKL are impressive lobbies. However, for me the Polynesian is my favorite. Being from Michigan nothing says vacation like Tropical vegetation and the smell of waterfalls.