A third alternative to consider is the crop body "equivalent" of the 24-105, which is the new EF-S 15-85 f/3.5-5.6 IS USM. It's expensive ($700, I think) and slower. But it's stabilized. It actually covers a wider range than the 24-105 equivalently does on a full frame (i.e., 15-85*1.6 => 24-136), and
it has UD and aspherical elements. It's just that being an EF-S, it won't be labeled as an L. It's substantially sharper than the EF-S 17-85 IS USM it replaced. To me, this is the one if you want a great travel/walkaround lens that does wide to short telephoto.