I have thought about this quite a bit too, read all of the reviews etc. I don't have the lenses, but I would go with the 24-70. The 16-35 is more expensive, and for the price you could get a 24-70 and a 430EX for your issues with the 17-40. The 16-35 at 2.8 will not provide a lot of DOF close up. Group shots in low light may require stopping down and using a flash anyway. At that point there is little IQ difference between the 17-40 and the 16-35. Also with landscapes, usually you stop down to the point of parity between the lenses. While the 24-70 provides an extra stop and better bokeh than the 24-105. With that said I do like the look of the 16-35 the wide situational portraits it can produce with bokeh are great, these are much less common in everyday shooting. Good luck, I wish I had some extra money so I am forced to make the same decisions.


Tom