Welcome to APUG. A Nikon shooter as well, I started my "black and white" filter collection with (Nikon's nomenclature) 52mm Y48, X0 and B8 filters (each has its own use in shooting portraits); later, and with an eye to shooting landscapes (now mostly shot with medium format using similiar filters), I added the R60 and O56 filters. Skylights, of course, are on the front of all my glass - a habit/lesson from my late father.
Recommending lenses is, of course, subjective, but count me as another fan of the legendary Nikkor 105mm f2.5 Ai or Ais (a very sharp piece of glass offering a very flattering perspective for photographing people). If, however, money is burning a hole in your pocket, the 85mm F1.4 Ais Nikkor is outstanding; be prepared to shell out in excess of $500 USD for a clean copy. In terms of longer glass, I would give a nod to the 180mm F2.8ED Ais and the 300 F4.5 ED Ais. As far as wide angles go any of the following can be recommended without qualification (price excepted...lol): 24mm F2, 24mm F2.8, 28mm F2, 28mm F2.8 (legendary sharpness -reputed to be Nikon's "best" wide angle), 35mm F2, 35mm F1.4.
BTW: Welcome to the Nikon family!
BLK