I've visted all 4 American zoos with giant pandas (San Diego, Atlanta, National and Memphis) and it is somewhat ironic that the zoo with the worst giant panda enclosure is the only zoo not to have at least one panda birth.
@PAT: San Diego is the only one of the 4 zoos that imposes a silence rule, complete with volunteers/workers standing guard and "shushing" loud visitors. The best exhibits for giant pandas are without a doubt the massive, lush yards at the National Zoo in Washington, D.C.
