I see Sigma do a 24-135mm f2.8-4.5. Would this be a good walkabout lens for my 350D? It seems to be in the ranges that I want, and stops down to 2.8 at the wide end (which I would generally use indoors for non flash photos). I can't find any reviews of this lens so perhaps someone can point me in the right direction or give me the benefit of their experience with this lens. Thanks.
See here: http://www.popphoto.com/assets/downl...2004165542.pdf
Since you already have a 75-300mm, I would go with one of the lens recommended earlier instead:
-> The difference between 70/135 is not that great (plus you can crop), but the difference between 24mm and 17/18 makes a bigger impact on the resulting images!