This may be a dumb question....
I know the 24-70 is the bread and butter for wedding photogs. I'm shooting my first wedding (free for family) in a month, but hope to start shooting some weddings for pay after that. Since I'm shooting a 40D, the 18ish to 55ish range is going to fill a gap similar to the 24-70. I currently have the 18-55IS, which is ok, but I would like to have more speed and a bit better IQ. The Canon 17-55IS would be ideal, but I can't put the money into it right now. I'm thinking about the Tamron 17-50 + Canon 85/1.8. I am expecting most wedding work would be with those two, the nifty fifty or 70-210 USM might see a little action.
But what about the AF in the Tamron 17-50? I finally tried one out yesterday and it was very loud. Sounded like RoboCop or something. And I have read that it doesn't focus very well in low light. Those two things make me wonder about using it during a service with low light, and noise a no-no. Is it not really that loud, and I was just paying too much attention? Would I be better off with a Canon 28/1.8 or the Sigma 30/1.4? Seems like a zoom would be worthwhile for weddings.
Edit: I guess the other lens I am considering is the 17-40L. I know it's more for FF, but should do a lot of what I want.