A Lowepro S&F Rover Lite (I think that's what it's called) takes care of anything up to my 4x5" camera with 4 lenses, or MF (ETRS) with three.

For longer travel I have a big Pelicase for camera and lenses - up to 8 - holders, Pola holder and lightmeters.

For the 5x7" beast I carry the lenses and holders in the Lowepro, and the camera in one hand.

My 18x24cm camera came with a suitcase...