The Nikon D7100 doesn't come with a screen protector, unlike many other Nikon DSLRs. There is not even a receptacle for adding one.
For my other cameras I always use a GGS LCD protector. It is a lot clearer than the plastic screen protector, and it provides more protection than the soft type of screen protector. In fact, it has already saved one of my cameras. See here.
What about the D7100? It is so new that there is no GGS protector for it yet. The good news is that you don't have to wait for one -- the D7100 screen is the same size as that of the D600, and can use the GGS protector for the D600.
But there's a catch...
The D7100 screen was designed to reduce glare and unfortunately, adding a GGS protector removes that benefit.
Here is the D600 with a GGS protector on the left. The one on the right is the D7100, before I attached a GGS protector. I bounced a flash off the ceiling. You can see that the reflection of the ceiling on the D600 is brighter than that of the D7100, evidence that the D7100 has better anti-glare properties (note: I don't know how the D600 without the GGS would compare).
After I applied the GGS protector, I did the same test. Here is how it looks:
Now the reflection is even (there might even be slightly more glare on the D7100). Here is another view (D600 on top, D7100 on the bottom).
Fortunately, the GGS protector does not diminish the brightness of the screen. In the shot below, the D7100 still appears brighter than the D600 (D600 on top, D7100 on the bottom).
PSA: If you are interested in the Nikon D7100, you can join the Flickr D7100 Group for samples and the latest discussions.