Probably 75mm (50mm f/1.8 on a DX sensor).
Just discovered that the Nikon 35mm DX actually covers the full frame on my D750 with only a small amount of vignette, so that’ll probably become a favourite somewhere.
DrJ – I avoided the 70-200mm f/2.8s for years just on the basis of weight, shot on a Tokina 50-135mm f/2.8 DX* which was pretty equivalent range but a fraction of the size and weight. Now have the 70-200 f/4 and absolutely love it – a lot of the benefits, but handholdable for an entire day without my arms falling off.
*which, coincidentally, is up for sale on the classifieds at the moment…