My Favorite is my Sears KS-2 (Ricoh XR7). It was my maternal grandfather's, which is probably why it is my favorite. It is quite easy to use, does all I need, and is my main camera.
I have a Voigtländer Vitessa and a Zeiss Icon Contessa (folding 35mm) that I really like. I love how robust they are, especially the Zeiss, and their engineering is a work of art. The Contessa is built like a tank, and while in sad shape from sitting idle in a second cousin's farmhouse longer than I've been alive, it still performs quite well. It has some bad lens fungus I've not attempted to remove yet. Once cleaned up, it will probably be my number-two 35mm.
Not a favorite camera, but one of my favorite camera situations, was with a point and shoot Kodak 35mm from the late 80s. It had a thumb-wheel film advance. When I asked people to take a picture of me with it, and it didn't auto-wind, they thought they broke it.