Canon EF-S 17-55mm f/2.8 IS USM Lens was introduced back in May 2006. It is the best EF-S lens that Canon makes so far. And it is the most expensive EF-S lens too. It is sharp, fast, fixed f/2.8 aperture and come with 3-stop Image Stabilizer (IS). It is the best general/multi purpose lens. It mounts at my Canon EOS 400D Digital body most of the time. 
