White noise is horrible to listen to. Brown noise is where it's at. Exponentially smoothed for the connoiseurs, get that soft rumble going.

White noise is an equal mix of all frequencies. It's what you get from radio static. It's hissy and nasty.

Brown noise is the sound of things being randomly bumped around (Brownian motion). It's what you get from waterfalls and thunder. It's smooth and delicious.