One thing the game, Pokemon Diamond/Pearl has is great music. No, really. Each game had its amusing ditty but D/P actually has some very worthwhile and epic sounding tunes. And they're on Youtube! Let me share my favorites:
Battle! Vs the Spirit Gods Vs The ChampionSummoned Beast BattleVs the Creation Pokemon (This one is pretty unusual)
Vs Cyrus (Cyrus has a great battle theme, really)