I know everyone raves about the Canon P, however it comes second in my eyes to its later sibling, the Canon 7. The viewfinder with its 35/50/100mm framelines is just too busy for me. Admittedly a beautiful design, and I will probably be labeled a heretic for this, it just doesn’t do it for me as a camera.
On the other hand, I love the 60 year-old collapsible Canon Serenar 5cm f1.9 from 1949. Six elements in four groups, I am making a guess that its a Planar design derivative.
I had the meter with diffuser, the humpback case, and the original instruction book too. However, its prettiness was not enough to overcome my functional dislike of it, and so I got rid of it. I kept the lens though.