If you plan to get any newer Nikon than the F or early F2's than I would highly recommend that you get Ai lenses. The non-Ai lenses will not work well or at all with some of the newer Nikon's. For-instance, they will not fit an FM2, FE2 or the FA and will only work in stop down mode with the F2A or the F3. I don't know about the F4 or F5. I have mostly the Ai or Ais lenses but a few non-Ai and can only use them with my F2. I am considering having these lenses converted here: http://www.aiconversions.com/PricesAndShipping.htm
As for the viewfinder screens, I have tried most and really like the grid screen (E) and have that screen on all my Nikon's.
If you can find an F2 in good shape, that would be a nice camera and you should consider it. I love my F2...very tough camera and it keeps on going even w/o batteries.