The 17-40mm is nice on crop tho, and is a good price. The 17-40mm on FF doesn't perform as well as others tho, it is a little soft in the corners.
I've got the 17-40L on crop because of the usual ff upgrade scenario - and though the lens lacks corner sharpness on ff (if you really need/want that) it's not that sharp anywhere on crop but outresolved by the sensor until f8. So for tripod brackets or bright daylight handheld it's very nice, good build quality and decent price (and it's a Canon, believe it or not :-)), but it definitely doesn't qualify as a photojournalism lens.
Reminder 1: Even if shooting ff with better iso capability you will still want to shoot at lower iso for the max. dynamic range, so the lack of IS might be still a problem.
Reminder 2: There seem to be more than the usual amount of "bad copies" out there, so check for decentering, I had to return my first lens. On stellar lenses like the 24-70ii a little less performance doesn't show until you're using a high mp camera, but with the mediocre 17-40 sharpness every problem shows.