I apologize for the long post.
For a while now I've pretty much made up my mind to get teh 16-35 purely because of the f/2.8 to be used on a 10D. My main reason for getting this is for photojournalism purposes, I'll be working for my college's school newspaper and I'll be using this equipment for my newspaper internships and freelance work once I graduate. To be honest though, my photo experience for a newspaper is very very small so I don't know for sure how much I'll be using the 2.8, this is just what I've heard I will need.
As a side note, I also want the wide angle to do landscape/nature work but obviously don't need f/2.8 for that type of work.
I would love to save the money and get the 17-40 f/4 L, but I'm afraid I'll wind up wanting the 2.8 for indoor/low light work. I'd also look at 3rd party lenses like Sigma or Tamron, but the build quality and sharpness on the Canon's really appeal to me. Although, newspaper print will never show it . Not too far down the road, I do plan on getting the 70-200 f/2.8 IS L to go along with my wide angle and my 50 f/1.8.
I guess in the end, I feel the 1 extra stop seems like a rip off compared to the 17-40. I know I can gain a stop on the wide end and save money on a Sigma or Tamron that have a max aperature range of f/2.8-4, but I always seem to read mixed reviews of these.
For my purposes, why would I not want the 16-35? or why could I live with something else to save money?