After having a look at my needs, i'm thinking a wide angle lens would be more useful than a telephoto. I've found two Canon lenses, the 10-22 f/3.4-4.5 EF-S and the 17-40mm f/4L EF. I have a 40D at the moment, and I'm not thinking of upgrading to a full-frame camera any time soon, so the EF-S mount isn't a worry. From what i've read, these are both great lenses, but i haven't seen them compared. I'll be using it for portraiture and architectural photos for a magazine I'm working on with a mate. Which one would you buy given the choice? Is there a superior 3rd party lens I should be looking at?