I'd say the NES because it flourished after the dreaded 1983 videogame crash, but my answer is the PlayStation 2. Incredible how such an underpowered console managed to sell so many units and have a vast library of games on it.

He provided relevant data debunking nonsense and all you got is ad-hominem bullsh. lol. As if his console of choice somehow affects the numbers.

If you were there and still think what you're saying then you simply weren't paying attention. Maybe you were a kid yourself back then and thus could not experience the many great games catered to the older crowd.

Sony did a great job marketing the PSone and had a killer strategy losing out on a lot of money to get third party developers on board. But the idea that these people would not have been there making these games had it not been for the PSone is nonsense. If anything, maybe we see less of the shovelware we saw on PSone if Sega or Nintendo were the market leader and naturally saw less sales. Is selling a ton of hardware automatically a great thing now? Do many of you claiming the PSone is the winner here, look back at the Wii library and say it was amazing? I highly doubt it.

Like someone else said, gamers who were kids with the NES were adults with the PSone. It makes sense more mature oriented games fared better. Not only that, but technology improved. A game like Dungeon Master II on Sega CD was just as mature oriented as Resident Evil on PSone, it just didn't look nearly as good. How creepy would Guardian Legend from the NES had been if it were a PSone game? Every genre exploded on PSone. Doesn't mean they weren't already there before. Sure it had more mature games. It had more of all the types of games. Again, doesn't mean they weren't there before.

Like the rest of the correct people here, I voted NES. The PSone would be a distant second. I can't imagine how the industry would look if the PSone never released. Nintendo made some bad mistakes with the N64 they likely still would have made. I doubt Sega rushes out the Saturn if it weren't for the PSone, but it's still probably a nightmare to develop on. But the industry still would have been here. The NES actually turned the industry around. Fucking lol at the idea that PSone "saved third party developers". Give me a break. Yeah, praise Sony on one hand for all the expansion they achieved but on the other hand ignore all the problems that have come of that and all the hell it has caused for developers.

Dreamcast gets the bronze. It introduced the console world to built in Internet access and pay to play multiplayer. Pioneered the online world that now dominates the industry. Also has an exceptionally high amount of amazing games for such a short life.

We always expected a Nintendo-majority forum to pick the NES but its success was mostlyluck and Nintendo could not sustain that success with the SNES. I maintain that gaming as we know it today has survived thanks to PlayStation. A small market could never have sustained the cost of games development without that expansion.

The NES, the mother of all modern gaming consoles.

Being first doesn't always equate to being the most influential in am area.  As I said in the very next sentence, online gaming was a novelty type concept on consoles, not much used or talked about except in a small handful of games.  And the Dreamcast wasn't the first attempt either.  The Famicom modem, the Sega Net Work System, the Sega Channel, the Xband, the Sega Net Link, the Apple Pippin, the N64DD, all these were attempts dating back to the 3rd Gen to bring online gaming of some form to consoles.  And all failed, all forgotten, all merely novel ideas.  It was the Xbox that changed that, that made online gaming a necessity.  The clearist indicator is the behavior of the market.  The Dreamcast launched before the GC or PS2 with its online functionality, yet neither of those two competitors bothered to have online functionality at launch.   The Xbox comes along with its online functionality and the games that take advantage of it and very shortly afterwards both competitors are playing catch up to them in that area and the next generation comes along and all consoles have built in online functionality.  

A couple of things wrong here:

- The console market crashed in 1983 in the US only

- The console market crashed because Atari (having been sold) messed up badly and bad games just flooded the market.

The Wii should be on this list, along with the NES, PS1 and PS2 it expanded the market.

LOL those are all third party games I am talking about first party games.

PS2 wasn't that underpowered it was more powerful then the Sega Dreamcast which started the 6th generation.  The Wii on the other hand was really underpowerd compared to the 360 and PS3.

This is, without a doubt, the biggest load of bull I have read since joining this site. 
Mostly luck? How was Nintendo anymore lucky with the NES than Sony was with the PlayStation? 
And the reason why the SNES didn't do the same numbers is because Sega kickstarted the 4th generation by releasing the Genesis much earlier - October 1988 in Japan, August 1989 in the North America, August to November 1990 everywhere else. The SNES? November 1990 in Japan, August 1991 in North America, April to September 1992 everywhere else.
Sega had a 2 year headstart over Nintendo. Giving them all the time they needed to amass a larger library of games over them, stealing a chunk of their install base. Like how Microsoft took nearly half of Sony's from the Xbox/PS2 generation into the 360/PS3 generation. If you think that having a headstart is insignificant, you're kidding yourself. And the SNES still soundly defeated the Genesis in the end. 

And you have an odd definition of "small". Using the numbers that zorg1000 pointed out:

Worldwide market:
3rd Generation - NES/Master System/Atari 7800=~75 million
4th Generation - SNES/Genesis/TurboGrafx=~100 million
5th Generation - PS1/N64/Saturn=~140 million

America
3rd Generation - NES era=~40 million
4th Generation - SNES era=~50 million
5th Generation - PS1 era=~60 million

Japan
NES era=~20 million
SNES era=~25 million
PS1 era=~30 million

Europe
NES/Master System era=under 20 million
SNES/Genesis era= under 20 million
PS1 era=~45 million

By the time the PlayStation entered the scene, console gaming was already very popular, more popular than it had ever been at that point. Sony is responsible for the explosion of the European console market, which they absolutely deserve credit for, as well as standardizing CDs as the main format for games and video game consoles as multimedia devices. For that, I consider the PlayStation to be the 2nd most important system in video games... but a distant 2nd. It was the NES that saved the American console market from the crash of 1983, created the Japanese console market (opening the door for what are now PlayStation centric franchises that were/are mostly popular in Japan like Final Fantasy and Dragon Quest, both of which started on NES.) During that period, playing video games was called "playing Nintendo".
If there was no Nintendo Entertainment System, there would be no PlayStation.