"Flightpath" is an aviation show on the Canadian derivative of the Discovery Channel. They have ranked the top 50 aircraft of the century. These have been split in to ten categories, five each.
Flying Boats and Floats
-Goose
-Beaver
-Catalina
-China Clipper
-Lake Buccaneer
Military Transports
-Douglas C-47
-C-130 Hercules
-Caribou
-C-5 Galaxy
-Antonov 225
Helicopters (military and civilian)
-Bell-47
-Apache
-Sikorski S-61
-Bell UH-1
-Boeing CH-47
Trainers
-Tiger Moth
-Kaydet
-Chipmunk
-T-6 Harvard
-T-38 Talon
Piston Engine Fighters
-Spitfire
-P-51 Mustang
-Bf109
-P-38 Lightning
-A6M Zero
Bombers
-Lancaster
-Boeing B-29
-B-24 Liberator
-Mosquito
-Boeing B-52
Light GA
-Piper Cub
-Cessna 172 Skyhawk
-Piper Comanche
-Beech Bonanza
-Learjet
Commercial Transports
-Boeing 707
-Douglas DC-3
-Constellation
-Boeing 747
-Concorde
Jet Fighters
-Harrier
-F-16 Fighting Falcon
-F-86 Saber
-F-4 Phantom
-MiG 21
Special Purpose Aircraft
-Wright Flyer
-Space Shuttle
-Bell X-1
-Voyager
-SR-71 Blackbird
In the top ten in no particular order are: Beaver, Bell 47, Herculese, Cessna 172, DC-3, F-86, Harvard, Lancaster, Mustang, SR-71.
You can place your votes at their website. Their site also includes facts and pictures of each aircraft listed above. Visit http://www.exn.ca/flightpath/categories.asp