35 MM FILM
To me, celluloid is without doubt the best medium to photograph on. The colors and imperfections can't be replicated on a digital sensor. Our own eyes are photochemical as well, not digital, so there's a greater level of immersion and realism that you feel when looking at film.
I also have a heightened experience from behind the camera when shooting 35mm. I'm limited to only 36 exposures, so I'm much more thoughtful about how I compose, and when to take the shot - which connects me further into the world of the image.