Diamond was great! I think I liked Platinum more because it was more set to the Winter theme.

Also with Diamond I started using Action Replay for awhile and there's some weird bugs in the game xD. Therelike some wood or stone statue left behind from one of the bugs. I was changing my character's appearance around a few times. In the middle of one of the streets it left behind that statue like figure of the female trainer. Can't remove it without deleting the save file either. I managed to turn him into a Pikachu too, but that doesn't last long. Especially the more battles you get into. I think my favorite of the AR things was catching an opponent trainer's Pokémon. You instantly win the battle when that happened. So it made the battle against the Champion too easy. Plus it was an easy Spiritomb haha. I don't do AR stuff anymore. I don't like cheats and prefer it more fair.