MrSandman
Team RC
You guys have a similar lens lineup as i do. I have both the 24-70 and the 70-200 2.8 IS and also the 100 macro. Also have the 17-40 and a couple other lenses but what you choose to have next is all dependent on your shooting style. I only use a flash as a last resort as my style i'm finding (especially with the 5D) is to crank up the ISO and use available light. I've used all these lenses on both my 20D and my 5D2 and they have their upsides and downsides when used on a crop body. On the 5D everything just fell into place perfectly. I was in the same dilemma as you. Get the 10-22 or get the 17-40? I am glad i got the 17-40 because once i got the FF body, the 17-40 was just stunning on it. Using a flash properly is not easily done. There is a steep learning curve and it takes alot of practice to use a flash and have your pictures come out like you didn't use a flash. (if you follow me). Have you considered buying a fast prime? Maybe even the 50/1.8?