I'm looking to rent a lens for an upcoming vacation in Arizona and I've narrowed it down to two, the Canon 10-22 and 17-55 2.8. Currently my widest glass is only the 28-135 that came with my 40D so you can see the need for something wider. Eventually I'll probably own both of these, but right now I like to try one out. Any thoughts on which would be the better option? I'll be mainly looking to shoot landscapes while I'm out there.