I can vouch for the 17-55 f/2.8. I have it and combined with my Canon 7D (I decided not to go with the 5D for now), it’s a great combination. The 17-55 is regarded as quite possibly the best ‘every day’ zoom lens. Love it.
I also had the 18-200 IS which I sold to fund the 7D and 17-55 and that was a very good lens as well.
I’m transitioning to mostly a wedding photographer.
If you look at my site, www.ilyakolproductions.com , the last wedding I did (Slavik and Tanya) was with the 7D, 17-55, and 50 1.8.