Dragon Quest singlehandedly created the console RPG style, which practically every game in the genre has utilized since its creation. While not as globally successful as Final Fantasy(in Japan, it's practically a religion), Dragon Quest came out first and has been more influential, and that wins it a spot on this list.
Legendary for its incredible cinematic story(it was the first game to utilize cutscenes extensively to tell its story), awesome graphics and sound, and frightening difficulty, Ninja Gaiden was hardcore action gaming at its most pure. The series would continue with these trademarks to the present day, and would even spawn a sister series, the Dead Or Alive series of fighting games.
#8: Mega Man (NES)
Ah, Capcom's Blue Bomber. Second only to Nintendo's big three, probably no series in videogaming has had such an enduring main character as Mega Man, and the series has spawned many different gaming series revolving around the character. The NES by itself had SIX entries to the series, and with the different spinoffs and versions across myriad systems, it is probably the series with the biggest amount of games in this Top 10.
Few series in videogaming have the old-school charm that Castlevania continues to have to this day, and when it was released, Castlevania was a HOT game. Tough-yet-fair gameplay, incredible graphics for its time and arguably the most memorable soundtrack of its generation make Castlevania an all-time classic, and it is still to this day one of gaming most enduring franchises. I expect for every gaming generation from here to infinity to have at least one Castlevania game.
#6: Metal Gear (NES)
While the 8-bit incarnations of the series were nowhere near as popular as other series on this list, the fact remains that Metal Gear was the first game in one of videogaming's most prestigious and innovative series. The series has evolved from a simple action game with a never-seen-before stealth premise into a genre-defining masterpiece of storytelling. Hideo Kojima used every resource in his power to make the first game of the series as unique a gaming experience as you're likely to find, and each following game of the series has used the same mold to become one of its respective console's best games.
#5: Tetris (NES)
While it was released for other platforms, it was in Nintendo consoles that Tetris became the phenomenon it is today. No other game on the planet is as simple-yet-challenging, accessible, or has the ability to suck in gamers of every demographic imaginable. Tetris is a testament to the incredible power gaming has as a medium to reach every single kind of audience.
Nobody in the industry, including developer SquareSoft itself, had any idea that its supposed swan song would become the premier RPG franchise in the world. Created as a last gamble as the company was going under, Final Fantasy was a game made with much love and dedication by a group of designers who wanted to do one last great gaming experience. This gamble payed off a million-fold: Final Fantasy became one of videogaming's biggest console franchises(only Mario and Pokemon manage to beat it in sales). The game itself had an incredible story for its time, a simple-yet-deep game structure, a huge map to explore, and ball-busting HARD enemies. The series has gone on to be successful in every generation of game systems released since, with some of its entries vying for best game status for the systems they were released in(Final Fantasy VI, VII and XII being the most prominent).
The three top spots on this list obviously had to be reserved for Nintendo's biggest franchises, and Zelda is truly the biggest of them all. While IMHO it is not deserving of one of the first two spots(as I'll explain on those entries), Zelda's auspicious start was definitely a preview of the incredible gaming juggernaut the series would become. While Zelda was not the first game of its kind(I give that honor to Atari's Adventure), it trumped them all with a friendly gaming structure never before seen, but now endlessly imitated. Still, no game ever will come close to Zelda's perfection in this department, and the fact that Zelda is now arguably Nintendo's biggest franchise is testament to the quality and longevity of this series.
#2: Metroid (NES)
Many people might be surprised and/or annoyed that I'd put Metroid before Zelda on this list, but you have to look at it this way: Zelda was a refinement of an already existing type of game(the adventure/rpg type game), while Metroid created a completely new type of gaming experience. Metroid was a game that was daunitng: it had a scary, claustrophobic athmosphere, weird enemies, haunting music, and an incredible structure designed to reward exploration. Metroid also belongs in this spot for one truly outstanding achievement: finally breaking videogaming's glass ceiling and putting a strong female character as the protagonist. To this day, Samus Aran continues to be the videogame world's most famous and respected female, and part of the reason is the absolute excellence of the series. Metroid has always been a series that puts others to shame with its incredible depth and scope, and many games of the series are absolute pinnacles of the systems in which they were released(Super Metroid, Metriod: Fusion, Metroid: Zero Mission and Metroid Prime being shining examples).
Is there really any surprise? Super Mario Bros. is, quite possibly, the single most important videogame of all time, let alone the NES. It gave the world Mario, videogaming's first real superstar, and it was the game that finally gave the industry the hope to try and rebuild itself after the disastrous crash of 1983-84. It was innovative in every way a game could be innovative: it had its own physics system which could be exploited by resourceful gamers, it had a definitive beginning and ending with a clear goal to achieve, it had memorable characters and enemies still seen to this day, it had wonderfully colorful graphics, the absolute most memorable tune in videogame history, incredible amounts of level variety, secrets and powerups galore... No amount of accolades is enough for this most shining jewel on the crown of gaming god Shigeru Miyamoto.