I have the 10-22 and love it. Of the 3 you listed, it's what I would choose. It's faster than the 17-40, and wider than the 15-85. Don't forget about your camera's crop sensor (on my 7D I think the 10 is really a 16 mm). In my research, I read that some consider the 10-22 as L quality, but is labeled as such.