Id Software's Quake brought true three dimensional polygons into the development realm and explored the online play space above and beyond any other game available, even according to today's standards.
-Christopher James, EA Montreal
I believe it was Quake that defined how the genre would move forward, with the fully realised 3D environment and and the lightning gameplay. Although Doom brought the genre to the fore, Quake refined the idea into the prince that would one day be king.
-Sean McCafferty, Instinct Technology
Quake simply re-invented the idea of a FPS, with it's online deathmatch, the "big-bang" of FPS modification community, and also starting the graphic card add-on for the PC hardware market as well.
-Johnny Oh, Electronic Arts
Wolfenstein may have started the FPS genre but Quake defined it and made it the intense perspective driven experience that it is today.
-Michael Neth, NeXT