The age old question: what is the greatest Pokémon Generation? Well since 1996 at least...
http://www.ranker.com/list/best-pok-and-eacute_mon-generations/michael45jg,
Generation VI
Main Series Games: Pokémon X and Y
Generation VI introduced brand new 3D graphics that are not only stunning but also meant the end of sprites. The new Pokémon are amazing and definitely improve upon Gen V's mediocre bunch. Horde battles are always cool if not a bit frustrating and the homage to past games only improves upon the game. Come on Pokémon Z! Ruby and Sapphire remakes could not hurt either...
Generation V
Main Series Games: Pokémon Black and White, Pokémon Black 2 and White 2
Gen V improved upon Pokémon's graphics but those changes quickly became irrelevant with Gen VI's switch from sprites to 3D graphics. Though Gen V's Pokémon certainty do not deserve much of the hate they get, they still are not the most creative and outstanding bunch of Pokémon ever. This is not helped by the fact that Black and White attempted to create a solid game with only Gen V Pokémon. Between the linear region and less than stellar Pokémon, Gen V is a fairly forgettable Generation.
Generation IV
Main Series Games: Pokémon Diamond and Pearl, Pokémon Platinum, Pokémon HeartGold and SoulSilver
Generation IV added many things to Pokémon. It make it clear that Pokémon could easily survive on the DS along with giving us some amazing games. Not only did it introduce the Pokémon Ranger series, but it also gave us Mystery Dungeon Explorers of Time and Darkness, which really proved that the Mystery Dungeon series would be around for awhile. Gen IV also introduced the physical/special split which revolutionized Pokémon as we know it. Before that whether a move was physical or special depended on what type the move was. For example, all Fire type moves were special. That means that moves like Fire Punch were special, which made no sense. Gen IV also introduced the most epic and enticing story line and criminal organization yet. Team Galactic, who seek to destroy the universe, attempt to summon Dialga, Palkia to achieve this end, but are stopped by the shadowy force known as Giratina. Giratina pulls you and Cyrus, the leader of Team Galactic, into its Distortion World where you are forced into a final battle against not only Cyrus but Giratina as well. It is truly the greatest most epic generation.
Generation I
Main Series Games: Pokémon Red and Blue (Green in JP), Pokémon Blue (JP only), Pokémon Yellow
It is time to accept the horrible truth, Gen I is not as good as you think it is. I know, childhood ruined right? But in all seriousness, Gen I suffered from tons of problems such as glitches, the special stat, poor graphics and so much more. To see a full list of all the problems with Gen I, please visit http://www.funnyjunk.com/channel/pokemon/Problems+with+Gen+1/nBoaGaO/
Besides, FireRed and LeafGreen made it so that we never had to return to Gen I again.
Generation II
Main Series Games: Pokémon Gold and Silver, Pokémon Crystal
Not only did Gen II introduce the new amazing region of Johto, but it also allowed you to return to Kanto and face off against yourself from the first Generation as the final boss. Gen II fixed a lot of problems from Gen I. It eliminated the many glitches that plagued the game, along with separating that silly Special stat into Special Attack and Special Defense.
Generation III
Main Series Games: Pokémon Ruby and Sapphire, Pokémon Emerald, Pokémon FireRed and LeafGreen
Generation III introduced much better graphics and was the Pokémon generation of the Game Boy Advanced. It introduced double battles, which today we could not imagine Pokémon without, introduced a great new criminal organization and a much more epic and legendary Pokémon based story line than previous generations. Some drawbacks to this generation are the overdose of water in an otherwise good region and many filler Pokémon. However, this generation remains one of the best.