* Ahhhh - This is the most common spelling for a long, drawn-out sigh of pleasure, relief, or amazement.
* Aah - This is a shorter, more abrupt version of the sound, often used to express surprise or pain.
* Ah - This is the shortest version, often used as an interjection or to indicate understanding.
Ultimately, the best way to spell "ahhhh" depends on the specific situation.