I was going to tag this thread but I'm way out of my league.
The 50mm f1.8 is a great choice.
I sold the 50 in favor of a 35mm f1.8. I like it better for the type of shooting I do. YMMV.
Take a look at a wide lens. Something 12mm or under at the wide end.
I rent the Tokina DX 11-16 from time to time (Yes I know it's a lens for a cropped sensor)
I really enjoy the ability to go really wide without a fisheye. Landscapes especially.
I can go down to 18mm with my widest lens and that's not always enough.
I think? Nikon has a couple of FX lenses that are really wide.
FWIW I'm a lowly DX shooter. (shuffling back to the kiddie table in the corner)
I almost forgot, a small flash. I have the discontinued SB-400.
This time of year I use it a lot for fill flash when the sun won't move where I want.