It's the only one I've flown so I'll vote for it -- and I'm a little surprised it hasn't shown up in this thread before now:
DC-3.
Glad I had a chance to fly a DC-3, at least once. 6/28/72, N1213M, Long Beach CA to Medford Oregon, 4.0 hr., signed off in my logbook by the CFI-captain as “1st officers duties – co-pilot checkout.” The airplane was being ferried to a new owner in Oregon and the captain needed a co-pilot on the spur of the moment to be legal. I took the rest of the day off from work to make the trip. All it cost me was airline fare back home from Medford, a bargain in my view.
I’m told that the airplane was scrapped a few years ago.
Weird coincidence follow-up to this story ...
A few months ago I was flying the 172 home to Washington State from San Diego. Flying more or less the same route from Southern California toward Medford, I reflected on that DC-3 trip so long ago.
Passing Medford, my reverie was broken by chatter on the Cascade Approach frequency. A Lancair Columbia was IFR from the Medford area toward Burns, and there were a number of transmissions between that aircraft and the controller.
All of a sudden I got a chill when I realized what callsign I was hearing from that Columbia: N1213M !! Same registration number as the DC-3 had.