Megamind and Monsters vs. Aliens are two of my favorite 3D BluRays and both will be available at Best Buy in September. Good 3D and storylines that are just as accessible to adults as children.
Tahiti: Ultimate Wave, Dinosaurs Alive, Grand Canyon, Giants of the Patagonia and Mummies: Secrets of the Pharaohs are all solid budget Imax titles ($15-$20 each at BB) with good 3D. They are primarily educational in nature and rather short (45 minutes each) but there is a lot of good 3D eye candy in each.
Hubble: 3D and Space Station 3D are more expensive Imax titles. Again, they are educational in nature and on the short side but the 3D is absolutely outstanding (outer space and 3D just work great together).
In terms of live action movies, Alice in Wonderland and Priest are entertaining and both have some good 3D moments. Both are post-conversions (ie. not natively shot in 3D) but still feature nice depth and interesting designs.
Those would be the standouts from my collection.
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