There is nothing quite as pleasant to my ears as hearing the bunnies eat.
Bunnies are quiet eaters; all you hear is the quiet crunching of the hay or the clinking as they push their food dishes are around a bit trying to get another bite. They are quite dainty eaters as well: unlike dogs, they eat their food in a dignified way, not casting it all about them in the course of trying to get it their mouths all at once.
Part of this comes from being prey, I suppose: with their eyes on the side, they can quietly eat - a helpful trait if you are prey in the wild - while keeping both eyes on whatever danger may be close by. But protected from danger - by living inside - it becomes a delightful and peaceful trait.
It is truly one of the most restful sounds in the world.