I have just inherited the most incredible gift. A canon 50D (barley used) and two lens. A canon efs 17 - 55 and a ef 70 -300.

I have been using a canon 400D for the last two years and have a basic understanding of this camera and the basic lenses that came with it.

I am going to buy a book to help me get the most out of the 50D but the lenses escape me. I haven't had much of a chance to play with them yet but which would be the lens I keep on the camera the most? Any information will be very much appreciated. I have large shoes to fill with this camera.