Based on your 2nd post, looks like you are using a APS-C camera. 17-40mm is a great lens for APS-C. Some poster may say that the 17-55 IS 2.8 is a better lens with about 80% more on the price tag. You will gain 1 stop speed and IS with slight increase in CA. I have used the 17-40mm for more than 7 years on a APS-C body. It is my main lens.
Likewise, the 17-40 is my main walkaround lens for the 7D, and serves me well. The range isn't as good as some of the APS-C dedicated zooms but it's still quite close to a full frame 24-70 with just a bit chopped off at either end of the zoom range.
I did a comparison with my 17-55 vs 17-40 on a 7D, I found them very close in terms of IQ. I think my 17-40 was slightly better but
then again it is an L lens so it should be! However, having f/2.8 and IS and a bit more length the 17-55 is my walkaround choice on the 7D.
Also the price difference between these lens is not 80%, I would say about 25-30% more for the 17-55.