Decided to play Pokemon: Platinum for the first time after watching JaidenAnimation's Nuzlocke vid. Never got around to playing anything from Gen IV and I really missed out. The physical / special split is a godsend (I also appreciated it in the later games I played), the then-new batch of Pokemon has some real winners, and the postgame content is substantial. Right now I'm getting whichever 'mons I want so I can keep playing around with the Battle Frontier.
I haven't gotten this much out of a Pokemon game since I was a kid - even my Crystal playthrough last year didn't scratch that itch. If you're in the mood for one of these kinds of games but haven't played this one, check it out. It's probably my favorite even without nostalgia.