I leave the peels on - better for you and more interesting to look at. I have several variations - one with butter/margarine, milk and salt & pepper, another with sour cream and salt & pepper, another with chicken broth and salt & pepper, a third with butter-fried garlic and butter, a fourth with butter-fried garlic AND onions and the last would be with whatever cheese I have on hand, along with butter, milk and salt & pepper.
Just depends on how fatty I want to make it. I currently have gall bladder issues so have been doing the low-fat versions lately.