In no particular order:
UH1 - helicopter workhorse which created manoeuvre warfare.
C47/DC3 - the first realistic AT.
C130 - ubiquitous second gen AT.
HS Trident - 1st commercial Cat III autoland
747 - intercontinental travel system that created true profit
Airbus (various) - changing the World with commercial FBW ethics, but not quite there yet.
B52 - global strategic projection.
CH47 - a monster SH capability.
Predator/Global Hawk - the future.