Which starter is the best?

[Liam]

^Yes, because everyone uses Staraptor.

[Avalanche Absol 137]

No, almost every new person to a game like diamond and pearl uses the pokemon at the beginning which you find there. Such as Staraptor (starly when they get it).

[mr.taco]

Turtwig. I asked my brother and he starting crying.

[Jake & Infernape]

CHIMCHAR!!!

he beats:
eterna
canalave
snowpint

[mr.taco]

CHIMCHAR!!!

he beats:
eterna
canalave
snowpint

well turtwig beats everybody mwahahahahahahahahahahahahahaahhahahahaha

[Reshurott Inferno]

Piplup is the worst starter in Gen IV, because of movepool, so don't pick it.

[Zombiekiller23]

Piplup/Prinplup/Empoleon! Even all my pokemon adoring friends agree!!

[Reshurott Inferno]

^In D/P, the best moveset is Surf/Ice Beam/Flash Cannon/Hyper Beam, which is the same for Platinum until after E4, when you can learn Signal Beam, so Piplup (in my opinion) is the WORST.

Torterra can learn Wood Hammer, Stone Edge, Earthquake, Crunch, which is an excellent moveset.

Infernape can learn Thunderpunch (Platinum), Flare Blitz, Close Combat, Earthquake, Stone Edge, Shadow Claw, which also is an excellent moveset.

[mogusama]

Turtwig is the best starter of all starters because its last evolution has ground grass
grass beats water and ground beats fire so its a very good choice BUT sadly chimchar evolutions are fire FIGHT so fight beats ground but id still reccomend turtwig

[Meowstic Royalty]

My favorite is probably Chimchar. Sure, I know the others have their advantages,  such as Empoleon being a Steel Type and Torterra being a wall paired with Leech Seed and Synthesis, but I like Infernape for a number of reasons.

First, it gets advantages on both of the other starters. Fighting against Empoleon, and Fire against Torterra.

Second, it gets a wide variety of moves, including Earthquake, Stone Edge and even Grass Knot to take out Water and Ground types.

Thirdly, few Pokemon surpass it's speed. It is designed to land a powerful hit before the opponent can attack.

[I am seviper hear me hiss]

Which starter is best? Hard to say, there all good for most things. Though when I started with piplup and trying to defeat that team galatic girl Mars from the windworks and I just couldn't defeat her.
So I would say Chimchar and Turtwig are really good starter pokemon, I'm not sure about piplup cause I never used it after that. So yeah Chimpchar and Turtwig!