I too am a big fan of metal, mechanical, manual (3-M) cameras. I have used Canon and Nikon 3-M cameras but I have never used the Canon F1. However, I had colleagues who used and loved them.
If I were in your situation, I would get the Nikon F2 (another great 3-M camera) so I could use the Nikon lenses I already owned. However, if I have always wanted the Canon F1, I would get it because life is just too darn short.