I'd like to have the playlist columns in the order Artist-Title-Album-Year
(RB currently doesn't know about the year, btw).  Besides simple
drag-and-drop of the column headers, there is another possible UI: instead
of simple on/off tickmarks, the columns could be added to a list in the
desired order.  Galeon does it with its toolbar building dialog: a bisected
window, one half has the unused icons, the other the used ones, and the
user migrates them as needed.