Depends on what you gonna take pictures of. I think in the dark environment Image Stabilization is more important, if you shoot interiors or landscapes. For people and other moving objects bigger aperture is a must. As an option (quite costly though) is Canon EF-S 17-55/2.8 IS USM. But cheap nifty-fifty (EF 50/1.8 ) along with EF-S 18-55IS might make an extremely cheap and surprisingly capable duet for your needs.


......I don't see a new 17-70 model anywhere on Sigma's home page. The only 17-70 lens they have (the same that I have), starts at f4.5 when at the 70mm end. Are you sure we're talking about the same thing here??

