Things that make me go mmmmm... the common sound of enjoyment, contentment and delight.
And then finally, inner peace. It is a sensation that isn't restricted to any sense. Indeed it is a spiritual thing. Although I include it tentatively because I can't say it is something that makes me go mmmmm because I can't say I've ever experienced it properly. The fleeting moments I have enjoyed have either been driven away by my own stupidity or torn away from me by the actions of others. But I hope it comes my way, one day. Preferably soon.