There are favorites, and then there are all-time favorites.
The favorites list changes as I use different cameras. Lately, it's been a Rolleimatic, Agfa Optima-Parat half frame and a Contax IIa.
I probably don't have just one all-time favorite. I have a list of five, which also changes occasionally. This might include a Rolleiflex Automat, a Rollei 35T, Contax IIa, Nikon F2A and (2005) Zeiss Ikon.