Peel potatoes, and cut into 1-inch cubes. Place potatoes in a medium saucepan, and add cold water to 2 inches above potatoes. Bring mixture to a boil over medium-high heat, and boil 15 to 20 minutes or until potatoes are fork-tender; drain. Return hot potatoes to pan, and cook over medium heat, stirring occasionally, 1 to 2 minutes or until moisture evaporates. Remove from heat. Mash potatoes to desired consistency with a potato masher. Stir in Cheddar cheese, sour cream, buttermilk, chipotle peppers, and salt. Return pan to medium heat, and cook 1 minute or until thoroughly heated. Serve immediately.