I second the EF-S 17-55mm f/2.8 IS and the EF 70-200mm f/2.8L IS II vote.


My first non-kit lens was the EF-S 17-55mm f/2.8 IS and and my second was the EF 70-200mm f/2.8L IS I. I still love both lenses and have never regretted either purchase. I have since added the EF 70-200mm f/2.8L IS II and it is outstanding. I tend to shoot a lot of non-flash indoor sports and f/2.8 or larger is a must for me, which is why I favor these two over the others for a two lens kit. As for the weight of the EF 70-200mm f/2.8L IS II, once you see the images it is capable of it really seems lighter.