I had the 17-55 and I don't get how it is called a "walk around lens" Imo
Is a great lens, but i think is more of a studio lens (just My Humble Opinion, please dont kill me), just like the 24-70 f2.8 on FF,
but as a only one lens for me is not wide enough for many things, is not long enough for other and even not fast enough at f2.8 as I kept using my flash indoors, not to mention pretty big and heavy for walking around.
I guess is a matter of opinion choice and style?
That is why I sold it and got the 15-85IS, I dont regret my desition.
But if studio is your every day thing on a crop I'd choose the 17-55 I guess, but even then on studio you don't really need f2.8, if you want shallow DOF i'd go for a faster prime also if you need low ligh again i'd get a faster prime but constant aperture is nice to have.