We should make the mods retitle the thread "AIRPLANES ARE FUCKING AWESOME HOLY SHIT"
For military prop-jobs, my vote goes to the Grumman F7F Tigercat, Grumman F8F Bearcat (bonus mention of Rare Bear, my absolute favorite air racing plane), and the Northrop P-61 Black Widow.
Civilian prop-jobs are the Lockheed Constellation, Delmar Benjamin's homemade flying replica of the GeeBee R-2 (now in a museum, I was lucky enough to see it do several aerobatic routines when I was a kid), and the Super Guppy (can't remember the manufacturer, but it's a one-off machine anyway).
For jets, F-35 and Gotha Go-229.