Wow, some of those buildings are incredible works of art. It's an experience just to approach them, to say nothing of the theaters inside.
FWIW, I've seen a couple of "real" IMAX films (not 35mm blow-ups) in the Cinesphere. And I've also been to the OMNIMAX in Portland, OR and the IMAX theatre that was in the Luxor Hotel, LV. (Apparently it was closed in April, 2008.) Saw IMAX's older active-glasses 3D at the latter.