I wouldn't be able to do that on an important trip or vacation. I always need at least 2 bodies that can handle the same lenses in case one broke. Its also convenient if you are shooting two different types of films, or want to go between different focal lengths without lens swapping.
But for everyday, and simple photo walks, sure one camera one lens is perfect. Today I headed out to Governors Island and went at it with a Bessa R and the 52mm 2.8 Industar I wanted to test.