I might be a little late, but my copy of the 35-70 loses a TON of contrast in bright scenes. For example, shooting a portrait at sunset with the sun at my/subject's side. It is heavy, for sure. I use my 50mm 1.8 or 55 1.2 most of the time, although that may be a little long on your D90. I also have a 24mm 2.8 prime. It can be a bit soft in the corners and has some distortion, but it's still pretty good. Not to mention the 50+24 combo is MUCH lighter than the 35-70 alone. Might be something to consider, and it probably won't be attached to a D70!