EvanK, the reason for Nikon was quite simple: my wife's employer requires the use of Nikon cameras. I am unsure if this is for software reasons, or consistency for evidentiary reasons, or the whim of some admin type. She was an Olympus fan during the film era.
Nikkor lens are not a requirement. Her agency-issued combination had been a D300s with a Tamron 18-200mm zoom, before the D300s cameras were pulled from the investigators to use as lab cameras. The pool of shared D200 cameras seems to include a mixed bag of Nikkor and Tamron zooms. After buying her the D7000, I bought her a Tamron 18-200mm super-zoom, and she get amazing images with it, in spite of the predictable compromises.
I have offered to buy her an optically better zoom, with less zoom range, but she really seems to want to shoot 18mm to 200mm without changing lenses.
The D7000's amazing performance at high ISO settings has me wondering if I should get myself a D7000, too, in spite of my heavy investment in Canon bodies and L lenses. For now, I am trying to be patient, as the price of a D7000 is a large portion of the price of a full-frame camera, such as a Canon 5D2, or Nikon D3 or D3s.
Canon 5Ds R/7D2/7D/5D/40D/1D2N/M3; Nikon F6/D3s/D700/FM3A/1Dx/Coolpix A. Lens selection changes often; some of my favorites: Zeiss ZF.2 2/135 APO, Canon 100mm f/2.8L Macro IS, Nikkor 14-24/2.8G and 24-70/2.8G.