I'm in the same exact position as the original poster. I too have a d90 and will be using it for dance recitals, plays, and mostly for family. With my 17-55 2.8 lens (only lens I have), I find I still have to go to ISO 3200 to get a high enough shutter speed to stop motion/prevent blur. At this point noise becomes an issue. I'm leaning towards getting a nikon 70-200 2.8 vr2 but worried that after a while, it may not get too much use due to it being such a heavy lens (based on forum posts); although I have no problems with the weight of the 17-55 2.8. Perhaps I'm better off getting the D600 and prime. Right now, I'm saving $$$ because I absolutely cannot decide.