Here is my opinion (listed in descending order of priority) to this very subjective question:
1. Nikon F2
2. Nikon F4 (best manual focusing auto focus camera)
3. Nikon F3
4. Nikon F
5. Nikon FM3a (lacks interchangeable view finder)
6. Other Nikon FM series (except FM 10)
I have owned and used all except the last two.