wow all these responses and no one suggested the EF-s 10-22 ... if you are looking to take WIDE landscapes then at this time there is no better lens ...in my opinion for just this the Canons EF-S 10-22 ...on a crop body it the same perpective as a 16-34 ... as wide as one can get without going fish eye ... i have one for just the same purpose as you wish to use your ... yes i do agree the 17-55 is a great lens but will at the end of the day be no wider then the 17-85 you currently own ... and there you have one more thing to consider ... 10-22 AS WIDE AS YOU WILL FIND





cheers