i hope this thread doesnt get locked
i like all of them but my top 3 would probably be
crystal because it had the most new features a pokemon game has ever had and even though johto was short it had alot of fun missions which extended the gameplay time. and the rival was hardcore not to mention u could go to kanto and hear nice remixes of the song 
yellow because i loved how pikachu followed u everywhere and actually spoke so u kew how it felt. it was the only game that was based of the anime and it even had team rocket in it
not to mention it was the only game in existence where ypou could catch all all 3 started (not counting 3-d games) so yea
lol
diamond - well i actually like platinum more than diamond because of the new graphics/ slightly altered storyline and the fact that u can battle gym leaders again but i chose diamond cause i am 59 pokemon away from having a full pokedex lol 