I am considering purchasing the Sigma 35mm for my 60D and it will be my first prime lens. I currently have a 10-22 and 17-55. I'm not going to sell the 17-55 immediately, but I anticipate that the Sigma will be on my camera most of the time. Most of what is shoot are travel photos. Landscape and snapshots of my gf and I. I am anticipating a move to FF but I don't quite want to go through the expense and trouble so I am hoping to upgrade more slowly. Deep in my mind, I'm hoping Canon would come up with something like the 5DIII but with a better sensor. Any thoughts or suggestions?