I've been out with the 7D a few times now and have some images piled up. I'll start with focal length samples.
Of course, if you're considering going from one sensor format to another you've got to include lenses in the discussion. I've already done this once - and then back again.
First, if I go all crop I'm giving up on the wide end with the lenses I have. So I took the 7D out with my EF 24-70mm f/2.8L lens. Here are shots showing the wide and tele extremes of this combination.
|24mm (38.4mm eq.)
|70mm (112mm eq.)
I could almost live with that being the extent on the side end. The main situation I'd want more coverage is with a sky full of colorful clouds.
One difference between the 7D and 5DIII is the former will only bracket three images whereas the latter will bracket 2, 3, 5, or 7 images.
I was framing the above shots in a way to compare the views of the two extremes. Here is a shot I made a bit later at 24mm with a more interesting composition.