Rotating motion is by far the most common case. This was the correct selection for the way that you shot your images.
Rotating Motion: used for when you stand in a single position and rotate your camera about a fixed point. This is how you should shoot most panoramic scenes.
The other motions are for less common stitching tasks.
Planar Motion 1: compute the best overlap between the images, but don't peform any skewing or perspective distortion. This is useful for doing multiple overlapping flat-bed scans of a large document. This can also be useful if you want to achieve a panography effect (although note that ICE doesn't have all of the blend modes that you might use for a panography.
Planar Motion 2: allow for skew between the images. Probably the least useful, but can be used if planar motion 3 gives poor results.
Planar Motion 3: allow for full perspective distortion between the images. This is useful for stitching images of a large flat surface, for example a white-board. As long as the object being photographed is flat you don't need to rotate about a fixed point like most panoramic shots and can move to capture different shots of the flat scene.
Automatic: this is the default. In this mode ICE will automatically choose based on the input set. Note that some set of photographs, especially those taken through a long tele-photo lens, can show up as planar motion 2/3 instead of rotating motion. This is one case where you may need to manually indicate the camera motion.
Also, note that the orientation adjustment view is currently only enabled for 'rotating motion'.