I ordered a Giottos protector from Berger Brothers when I recently got my D7100. It is a good fit, but does cover a bit of one edge of the screen. Since it is the left side with the icons in the menu, I'm not too worried about it. In a few months there micht be a better fit from GGS or Giottos. (My original D800 Giottos cover also was not a good fit, but6 months later there was a good replacement GGS available on Amazon.)
The D3, D3s and D4 all have tempered glass screens. Pretty close to indestructible adn certainly very difficult to scratch. I have never but a cover on my D3s, which is 3 years old and looks as good as new. But, I would not make the assumption that any other Nikon body uses tempered glass.
I do not like the film covers because of: bubbles, optical clarity and durability.