I have recently taken to using the 10-22mm for events. I have the 17-40 as well, but now I find it not wide enough. It's amazing how nicely you can get EVERYONE in the picture at 10mm, and how dramatic the shot looks.
The problem, as someone mentioned, is that at 10mm, the people near the edges have terribly distorted faces (sort of like getting caught in a black hole kind of effect). I've managed to get around that by using Panorama Tools (a freeware - just google it). Introduce a bit of fisheye distortion into the picture and suddenly all the faces look normal. The straight lines in the background become a little curved (Einstein's relativity at work again) but nobody looks at how straight the lines in the background are. They notice whether the faces are distorted or not.
Anyway, pictures are worth thousands of words:
After introducing fisheye distortion
After cropping out the black border
You will notice that one beneficial side effect is that the edges seem to GAIN DETAIL.