It used to be film that determined the look of a camera. Change the film - or the way it was processed - and the look would be different. But now the image-capturing element in a camera is the sensor, and it's fixed. You can't change it like you can swap a roll of film.
So the intrinsic properties of the sensor are important.
Most people know there are two basic types: CMOS and CCD, and that most cameras these days use CMOS. But that's not because CMOS is necessarily better.
Here's a fascinating account of why Digital Bolex Co-Founder, Joe Rubinstein, thinks that CCD is a better type of sensor, and why Digital Bolex chose it to front their D16 camera.
If you've ever wondered about this stuff, this is an excellent explanation.