I saw this on the D800 forum and so I checked if there is an existing thread for the d7100 but I didn't find any.
So, what lens is on your D7100 right now?
Mine is the 35mm f/1.8. Waiting for an opportunity to shoot something for the nifty fifty shoot.
I searched to find out if there is already a thread about this but didn't find any. So I'll start. I have D7100 and I consider the following as my trinity:
Nikon 10-24 f/3.5-4.5 af-s dx g ed
Sigma 17-70mm f/2.8-4 DC Macro HSM
Nikon 70-200mm f/2.8 VR