Got a loan of a 17-35mm Canon lens at the moment, to make sure this is what I want for Christmas last year (!). The thing I love about wide angle lenses is what they do to clouds, but we've just not had the right weather since I got it.
I took it up to a local reservoir yesterday to try to get some sunset pics, but it was pretty cloudy so I gave up. Just as I got to the car, the sun broke through some trees, and I fired half a dozen shots off to see what came back. Best of the bunch by a long way...