In particular the birdseye angled aerial images are awesome and allow you to see all four sides of structure, instead just a roof, with surprisingly good resolution too.
I was surprised a few days ago to find out that Google Maps actually has this. You have to be on a PC and browser that support WebGL (i.e. no "Lite Mode" in the bottom-right corner). Zoom all the way in with satellite view turned on, then use the controls in the bottom-right to tilt the image. Then you can rotate in either direction, at which point it uses a cool 3D effect to stitch together its views of the different sides of buildings.
(I haven't actually used the Bing maps in quite a while, so not sure how this compares).