Denise....sorry I can't help you w/your road trip, though Glacier would be a great destination.


My reason for replying is Brendan's statement concerning the 17-55 IS; "Just make sure It stays clean ~ dust is its biggest weakness."


I don't have an issue w/the first part of his statement, keeping your equipment clean is standard operating procedure. It's the second portion concerning dust being it's biggest weakness. I've owned the 17-55 2.8 IS for nearly a year now and haven't had a problem w/dust. And this lens has traveled thru NM, AZ, CO, UT, e.g. Mesa Verde, Mystery Valley, Horse Canyon and 2 days in Monument Valley w/a private guide driving us around MV....all very dusty environments. I haven't had to PS 1 spec of dust out of my photos taken w/this lens.


So in conclusion Denise, I haven't found dust to bethe 17-55 2.8 IS (nor in my other "dust" lens; the 100-400)biggest weakness....actually,it's weakness is probably me. []


Best of luck w/your lens....you'll truly enjoyit's results and enjoy your road trip, whatever you decide.


Regards


Bill