My favourite pokemon game is Emerald!! Then LeafGreen then Soul Silver then White. I played Crystal before but I liked SS/HG more, and Yellow was just so unplayable.. Anyways can't wait for the 6th gen!!
thi sis a series which doesn't really have a best game. its subject to what you grew up with or what title you jumped into first.
for me i grew up with yellow blue and red. so id have to say leaf green and fire red are the best game. i like a great amount of the pokemon in that game. however gold and silver on the game boy would be a good second choice.
for me i found each game got gradually worse and there were less and less pokemon which were likeable. so if history has taught me anything x and y wont be any different.
Gen five started out as not-too-great-but-okay, but then Black 2 brought the most enjoyment I've ever gotten out of a pokemon game. And they made breeding and training good pokemon a bit easier. It made it easier to breed the right nature onto pokemon with everstone, and I can get them up to level 100 easily with the level-up features in the Join Avenue shops. Before, I had only a team of six level 100 pokemon per game because training and breeding good ones was a pain in the butt and took too long. Now I have an entire pc box full of level 100 pokmon in black 2. They actually put in a good incentive to complete the pokedex in B&W2(the shining charm). I love that they gave a lot of pokemon great new hidden abilities. I learned to use the berry patch on the dreamworld website to grow custap and micle berries and sell them for 30,000 each in my game. I'm very rich in-game. Very rich. >: D In older pokemon games, there isn't such an easy and quick way to make that much money. Plus the story/adventure/whatever part of the game actually was a little interesting. So I have to go with Black and White 2 as the best games. Oh man, this game has sponged up so many of my hours. So many...
I'm expecting a lot of good features to show up in gen six. Maybe something as handy as join avenue. I will be very disappointed if they don't bring in anything good.