Just bought the EF-S 17-55mm f/2.8 for my Rebel XS. I love, love, love the image quality. However, shooting pictures in my house ("normal" lighting), I'm finding that to achieve a shutter speed of 1/60s or so, I still need to be at ISO1600 and f/2.8, which limits quality (noise) and depth of field. This means of course that my subject has to be still or blur occurs, something that can be tough with a 1-year old and 3-year old. Does this sound about right? Would a better body help or is it just a reality of light? If so, would an external flash help the situation (I hate the pop-up flash, hence the f/2.8 lens).