This is my new favorite lens. I haven't taken it off the camera since I got it.
Here are a few quick shots I grabbed while seeing what this baby could do:
These were all shot with a Canon 5D Mk II (except for the last one of Bruce -- Husky -- where I put it on my 7D).
This is really one of those lenses that you want a full frame sensor for (if you like that balloon-head thing I was going for in these shots, anyway ;) ). There are several more examples
on my blog if you're interested.

16mm f/9 1/60 ISO125
Manual
Subject Distance 0.3m

16mm f/9 1/60 ISO125
Manual
Subject Distance 0.3m

(left) 33mm f/2.8 1/500 ISO500 (Manual) *on the 5D body
(right) 35mm f/2.8 1/400 ISO125 (Manual) *on the 7D body