I bought my 60D last month with the Sigma 17-70mm f/2.8-4 DC Macro OS HSM. The IQ is really good. Aperture is larger f/2.8 to handle even in low light situations. The bokeh is nice with its 7 rounded aperture blades. And the focusing is very fast and it is very quiet due to it's Hyper Speed Motor. With Optical stabilizer that even sense tripod mount. And it comes with a free pedal lens hood.
Of course all these are my own personal preference and experience. Some people may still like the standard kit lens especially the kit II & III can cover both wide angle and long zoom range. For me I mostly shoot landscape, portrait & street photography. So 17-70mm is comfortable for me. Cheers!
thanks for advices, I shall start out with the kit lens lst. Maybe will upgrade to other lens as time goes.