If I had a Nikon F2 with a 50mm f/1.4 lens and wanted to expand my lens collection for shooting landscapes, still life, and portraits, here is what I would get in descending order of priority:

1. Nikon 28mm f/2.8 (for landscapes)
2. Nikon 105mm f/2.8 macro (for portraits and still life)
3. Nikon 18mm f/3.5 (only if I needed something wider than the 28mm)