The original Doritos flavor is Original "Doritos Toasted Corn" tortilla chips. I absolutely love them and have been eating them for many many years.
I have been here in Nashville, TN for 4 years from So Calif and can't get them out here. Frito Lay doesn't distribute them east of Texas. I have called them about it. Not many people remember these great chips. Most people asked think of Nacho Cheese flavor as the original.
Check out this link with a picture of the original bag: