I prefer 2", although I often avoid the whole subject by birthing my quilts. Early on, I was told to use 2 1/2" . Then a professional quilter said that the big shows judge on having the machine seam and the hand seam directly opposite each other. I don't always even try to do that, but 2" makes it easier to do. It is less work to do a larger binding, even with the clips I always use.