In my opinion, all plotlines of Pokemon Games are severely lacking. None of them are suspenseful enough to give the player a reason to keep playing, other than beating all of the gyms, as well as the Pokemon League. Out of all the main games, I'd have to say that Diamond/Peal/Platinum's storyline really stood out. I believe there was once a rumor going around, that the plot of these games was originally much deeper/darker, but was revised, due to Pokemon being a kids' game. That's not to say that these games don't have the makings for a great storyline, though. Unlike Ruby and Sapphire, as well as Black and White, Team Galactic actually had an extremely valid reason for using the power of their game's respective legend. The best part of the plot would have to be the antagonist himself, Cyrus. Cyrus is quite the interesting character, he having gathered legions of followers, united in a radical pursuit, with the power of speech, alone. We also get a glimpse of what led Cyrus to become the man that he is, through the dialogue of the NPCs found in one of the houses in Sunnyshore and the old man, living on Route 228. Diamond and Pearl led me to believe that the plot of Pokemon games would improve in the future, although the plot of Pokemon Black/White failed to set this belief in stone.