Steve,


I have all three lenses you mentioned. I got the 17-40 first, as my general purpose lens on my XTi and I loved it. But I have to say since I got the 10-22 and the 24-105 I don't use my 17-40 as much (only in certain situations). The 10-22 and the 24-105 compliment each other very nicely (when I want to travel "light", these are the only two lenses I carry). As it's already been said, the focal length difference between 10mm and 17mm (on a crop body) is huge. And I personally love shooting extra wide. It's not for all situations and you can totally overdo the effect, but I personally love it.


Regarding image quality, the 10-22 it's maybe not quite as sharp as the 17-40, but it's sharp enough so that I don't need to switch to the 17-40 for focal lengths between 17 and 22. Also, remember that typically extra wide lenses might not be as sharp as longer ones. And, BTW, some folks claim that the 10-22 outperforms in some respects the 17-40 when the latter is mounted on a FF body.


If you're interested, get in touch and I can point you to some shots I've taken with the 10-22 so that you can check them out.


Tony