With the exception of the Ai and AIS 28/2 and the AIS (NOT Ai) 28/2.8, Nikon's old manual focus wides were not exceptionally good. I have been through 4 copies of the 24/2.8 (one AF, the others Ai and AIS) and sold all of them. However, that said, while it's not mind blowing or anything, my 20mm f/3.5 AIS -- mentioned above by Robert Lai -- is really a favorite and wonderfully sized with 52mm filter. Of all the lenses discussed under 28mm, excepting the $$$Zeiss of course, the 20/3.5 is the one I'd recommend.
For 24's -- Nikon's can't touch Minolta Rokkor's 24/2.8 or Contax Carl Zeiss 25/2.8 or OM Zuiko's 24/2 or Leica R Elmarit 24/2.8.... (essentially the Minolta MD Rokkor) -- those are the competitors I have used.
I agree with all here that the new(ish) 16-35mm f/4G is outstanding. It's been criticized as soft at 35mm but I haven't seen it. Even if it's true, it's so sharp and rich in color from 18 to 30 it doesn't much matter. It's sharp at 16mm too but quite rrrouuunddd. (Barrel distortion, that is.) Still this is not a lens for your MF camera. For that I'd go either with the 20/3.5 or that Zeiss 25.