[Rover]

EF-S 17-55mm IS demolished everything when I was choosing a first lens (and this lens having IS was what made me choose the Canon system over the Nikon one, simple as that). However, that was 5 years ago. A Sigma 17-50 might be a viable alternative today. Plus I managed to grab one of those faulty early specimens of the 17-55, and that has soured my experience a bit. Still, had I been faced with the task of choosing a EF-S standard zoom all over again, I would've probably chosen the 17-55 again, I loved it so much.