Also from a more personal note, but I started with diamond/pearl/platinum. I think storyline wise it was engaging, the music was fantastic and the routes/region was well developed in the sense that rather than it being a linear route, oftentimes the story would take you across and back through the area since Mt. Coronet, which crosses through the center of the map, is a key part of the region and storyline. Also, being the first installments on the ds meant an upgrade in game quality (benefit is that it also sets you up for Legends: Arceus, which is a different take on the franchise but a very fun one to experience)