For what it is worth, here is my take on the 4 most historically important sailing ships.
In order chronological:
Phoenician Trading Ship - These ships were a major step forward in both trade expansion and the exhcange of culture between civilizations surrounding the Med.
Viking Long Ship - Brought the Norse to Europe, England and probably North America.
Santa Maria - Really a terrible ship, but as flagship of Columbus' expedition is credited with "Finding" the "New World".
HMS Victory - Not just as Nelson's flagship at Trafalgar, but as representative of the Britain's Royal Navy that dominated the oceans of the world for two centuries. This domination fostered and is, atleast partially, the reason the British Empire's domination of the world was as big, and lasted as long, as it did.
Just my two cents...