Canon - Zoom Wide Angle-Telephoto EF 24-105mm f/4L IS USM Autofocus Lens

Outstanding walkaround lens.  Works well in almost all enviornments.  This is the kit lens on the 5D, but I use it on a 20D.  Despite the required adjustment for the 1.6x lens factor, the lens still is a dream to use.  It has a really balanced range between wide angle and telephoto.  It produces sharp images, it's quiet,, easy to use, and light enough to carry around all day.  I give it my highest recommentation.