Unfortunately I think that all lenses that are looked at as "replacements" for the 18-55mm are going to be big and heavy (well, at least bigger and heavier than the kit lens).
f/2.8 glass or bigger zoom ranges come at a cost in both dollars and pounds (ok, BAD pun! or double entendre?)
Anyway, My new "kit" lens is the Tamron 28-75mm f/2.8. Only con (besides cost and weight) is the loss of the wide angle. But you get a constant f/2.8, much better image quality than the kit (although the kit lens isn't that bad), and it's actually not too heavy (compared to the Sigma 24-70mm, that one is a BEAST)
I was also considering the Sigma 17-70mm, but really wanted f/2.8 at the long end. I still put on my kit lens when I need wide, but I am looking to get something else in the wide range - either the Sigma 10-20mm, Pentax 12-24mm, or possibly the Pentax 14mm f/2.8.
Originally posted by Buddha Jones Actually, the lens that I like the most is the Sigma 24-135... but it is soo dang big and heavy.