This is one of those Joni Mitchel Big Yellow Taxi realizations - you don't know what you've got 'til it's gone.
So for me:
Kodachrome II (ASA 25)
Kodak HIE (high speed infrared)
Kodak Tech Pan
real Polaroid SX-70, 600, and pack film
Fuji FP pack film
"Great photography is about the visual effect upon the viewer, not sharpness." - Stephen Gandy, Cameraquest