ISO question for D7000 users.

With my D5100 (same sensor), I feel comfortable/confident pushing the ISO to 3200.  At 3200, it's easy to manage the noise with LR4. At 6400, it takes a little more NR in Lightroom and the images can start to look a little too soft.

I'd also like to point out at the Nikon's native ISO is 100. This means that the camera prefers to stay at whole stops (I.E. 100,200,400,800...)  If you pick something like 640, what the camera is actually doing is taking ISO 400 and compensating.  This can actually create more noise that just shooting at 800.