It appears that you have received some good advice. I picked up the lens over 4 years ago with somewhat the same idea. I am happy with it, however it is not a full replacement for a non fisheye or rectilinear lens. I would suggest that you download a copy of PTLens (its free) and get a copy of a 10-17 image with exif data so that you can play with the conversion, to see what you want to do.
Overall, as others have written, its a lens that when you have really large items or are really very close to something, its a lens that always comes through. I also have the 12-24 and the two paired together complement each other very well.
hope that helps...