Atari's Tele-Games Pong console essentially built the home game industry. It was the console that proved interactive television entertainment was viable as a consumer product. There's a reason why virtually all of the early consoles released ahead of the Atari 2600 were essentially Pong clones (Magnavox Odyssey and Fairchild Channel F being the two primary exceptions). Expanding on that, the Pong arcade system was also the first widely successful commercial gaming device, period.
Of course, given that the Pong idea was essentially cribbed from one of the Magnavox Odyssey's games, it could be argued that it was the most powerful console.
I'm not surprised NES is winning the poll, of course, but it's greatest impact wasn't global, but in the US market specifically. It certainly was an IMPORTANT console, with many games that either defined or built genres, but let's not forget: Nintendo's first entry into the video game market was a PONG clone, which was built because that initial Pong consoles was madly successful. EVERYTHING in this industry stems from that one little device.
