My 17-55mm is my workhorse, but every now and then a telezoom is nice to have. So far I've been hauling around Nikons 80-200 2.8, but on some assignments its simply too big to drag around all day, especially when I know that I'm not gonna use it. So I'm looking for a lightweight telezoom that I can carry on me at all times. So far I found Tokinas 50-135mm 2,8, Sigmas 50-150mm 2,8. Does any of you guys have experience with any of these, or other suggestions?