My main issue with choosing 4-5 is because the transition between these generations was a lot messier than 5-6. On top of that, there WHERE some 3D games on fourth generation machines, and some early 5th gen machines featured poor 3D graphics (notably Atari Jaguar) that really didn't look that much better than stuff like Star Fox and Virtua Racing on SNES and Genesis.

From stuff like the FX chip and 32X to early 5th gen hardware like Jaguar and 3DO, to Neo Geo, which was a really strong 2D machine from the fourth generation that was capable of going toe to toe with the 2D capabilities of 5th gen machines, I'd say that this transition was slower, messier, and more gradual than a lot of other generational leaps. 5th gen WAS pretty darn revolutionary in terms of game design though, certainly more revolutionary than any generation sense.

But in terms of a graphical leap, I'd say 6th gen. This was the gen that brought us huge 3D worlds, detailed 3D graphics, and advanced 3D game design.

I mean, let's not forget, the 3D graphics of the 5th gen were pretty much undetailed boxes stuck together to make characters and worlds.

6th gen brought us fully realized characters, with eyes that could move individually, faces that could form various expressions, FINGERS, among other things. Shenmue, Metal Gear Solid, Halo 2, Star Fox Adventures, Panzer Dragoon Orta, these games contained detail and effects never seen in games before.

Let's also not forget the birth of the wide open sandbox game. Shenmue and Omikron were early pioneers, but Elder Scrolls 3 and Grand Theft Auto where the first games that really did it. Before this generation, the closest approximation we really had were early WRPGs like the first two Elder Scrolls games, which were procedurally generated in sprite based pseudo-3D worlds, rather than painstakingly rendered and designed in full polygonal 3D like Elder Scrolls 3 was.

On top of that, even 2D games were finally able to move away from pixel art and utilize hand drawn sprites, that didn't need to be downgraded to pixels to work. Only a few games really utilized this (like Alien Hominid), since 2D games were more or less dead on consoles at the time, and the few that were made utilized either polygons or sprites.

4th to 5th: 3D, far larger address space thanks to 32bit, and PS showed ther could be another successful approach beside Ninty one. Sure, 3D wasn't always used in a visually pleasant way for the first times, but that was the revolution and proof of concept, after we just had refinements of it.

Definitely not Gen 7 or Gen 8. So I cheat and say Gen 0 to Gen 1.

I was obbsessed with Crash 1, but it didn't feel like an entirely new experience. For me, it felt like a logical progression from Genesis and SNES. I suppose if you jumped from SMB3 to that game, then it would have been much more impressive but that is a TWO generation leap instead of one.

SM64 reinvented the wheel. Not only was I playing my first 3D platformer, I was learning how to use an analog stick as well. It was like, a total WTF moment lol. 

I don't think we'll see another leap like that until VR gets it right... if it ever does. 

it was on 5th gen (3D) and will follow on 8th gen (VR)

Generations 1 to 4 were cartridge based systems restricted by the limitations of old technology from the 1970s to the early 1990s.
Generation 5: The Play Station (PSX) introduced CD format that significantly improved upon cartridges. Nintendo sticking with cartridges was a huge mistake and limited N64. PSX outsold N64 by a huge margin in world wide console sales. Third party developers released more games on the PS due to CD being easier to port/develop games than the cartridge based N64.
Generation 6: The PS2's introduction of DVD format, improved performance and storage capacity over CD format.
Generation 7: The PS3 introduced Blu-Ray player stores more content/data on a disc than DVD discs. 7th generation made online gaming and online game purchases and content popular during 7th generation.
Generation 8: Has been a run away victory for the PS4 over its competitors. 8th generation has been an increase in game console storage capacity and improvement in online gaming/content.

6-7 cause SD to HD, I dont think theres anyway any generation will ever compete with that, even going from HD to 4k isnt realy the same difference.

Definitely Gen 6 to Gen 7. As a Playstation gamer. You can see clearly the significant change of the graphics, gameplay, and pacing of the game from PS2 to PS3. Even the price or marketing of the products greatly increases. Like by comparing FF7-FF9 to FF10-FF12, Resident Evil, Tales of Destiny 2 to Tales of Xillia, Devil May Cry 3 to Devil May Cry 4, God of War 1 to God of War 2/3, Persona 1/2 to Persona 3/4.

Precisely why I said gen 2-3 was a big one as well. Also, I'm going to assume you're one of the few other over-30s on here as a result of that comment, so hi!

2-3

That's when video games became video games and not just home arcade.