Just got Diamond for B-day, and I haven't decided which starter to choose. Any ideas?
I think Chimchar is usually the best. It can learn fire blast and focus blast before the third gym and learn swords dance a bit later, and Infernape has better offensive typing compared to the other starters. It's also more likely to outspeed and one-shot opponents and less likely to give them a chance to use an annoying status move. The current world record holder in DP speedrunning used a Chimchar.
I suggest you to choose Chimchar as your starter Pokemon because After it evolve it into 3rd Evolution state that is Infernape its Attack and Speed increases greatly. Also it give trainer a good type coverage against opponent Pokemon.
I suggest you should teach your Infernape these Moveset :
2.Focas Blast (special move)
3.Close Combat (Physical move)
Chimchar is definitely the way to go. Infernape's offensive capabilities are monstrous in the mid and late game, but has a slightly slow start in the beginning, as it has a weakness to the first gym. Luckily though, catching a Budew just before the entrance to the city, the gym becomes very easy. Infernape is also the only solid choice for a fire-type Pokemon on your team, as Flareon and Rapidash are not great by themselves, nor do they hold a candle to Infernape.