but I'd acctually have to say, (putting aside all practical usefulness, anything rationally related to the simplifiication of programming and completely disregarding any saying about replacing the old with the new) I'd have to vote the line editor; Color BASIC preferably on a Trash-80, with the large big clunky 20 year old wooden cased TV that's fake wooden laminate is flaking from the corners and the missing channel tuner nob that has been replaced by a pair of pliers.
Oh, and not to forget the saw horse for a seat.
RC