Most influential system (and why)

[HoloDust]

Bofferbrauer2 said:

The NES.

Not just for reviving the console market (and bringing it to Europe btw), but also due to it's controller. Just compare the controllers of Atari 2600 and others of their generation and the NES: D-pad, Start & Select buttons (or something along those lines), AB buttons (which now have become ABXY with a second row of buttons), those have all become standard nowadays, as have holding the controller essentially sideways and not like a remote.

Hm...I'm not so sure about NES bringing console gaming to Europe - Atari 2600, Magnavox Odyssey 2 and Colecovision were all selling (relatively speaking) fairly well in Europe before NES, so it's not as if Europe didn't participated in console gaming, it's just that home computers were much more popular in Europe throughout 80s. And even with NES, Master System was initially more popular in Europe (for NES only to win in the end by fairly slight margin), both achieving only ~15.5 millions combined vs ~20 millions that 8-bit computers managed in Europe.

As for popularizing D-pad - depending on how much you liked arcade style games, D-pad was a curse, not a blessing, since such games played worse with D-pad than with proper joysticks. In the end, it is indeed most reasonable choice to include in the gamepad, since it has best ratio of usability vs space required, but not really the best choice per se.