So I want to replace my 18-55 kit lense on my canon. I currently have the 70-300, 50mm , and 100mm lenses. Which are all great but I want to be able to have a universal lense that I can take on trips that I can use with out changing the lense very often plus when my wife uses the 50mm or 100mm she hates it because you have to adjust with your feet!. So I was looking at the canon 17-40 f4L (I want to stick with canon).Its seems like a great price and Im sure it would be a great upgrade over the kit lense, but is it money well spent or should I get the 2.8 version or another canon lense? Like I said the lense will be used mostly for vacations, landscapes and for my wife to use with out complaining about swapping lenses. Thanks for the advice in advance!