Verified answer

First, whichever starter you chose is great. They are all very good. Personally i believe that Chimchar is the best one due to it's high Speed, Attack, and Sp.Attack, but all of them are great.

Second, i would recommend catching yourself a Starly on the First route. It is way better than the average Pidgey with is better stats and great moves.

Finally, it really doesn't matter who you choose. There is alot of good Pokemon out their. I would recommend saving a slot on your team for an HM slave, a.k.a Bibarel, as there are many HM's you will need.

Have Fun!

Definitely go for Chimchar because when you have Infernape and your rival has Empoleon (Water/Steel) Fire attacks will be Normal Effectiveness and Fighting attacks will be Super Effective. Try to catch a grass type pokemon for back-up and train it so it relatively keeps up with your Chimchar/Monferno/Infernape, Goodluck! :)

(Here is a link to a superior walkthrough)

http://www.psypokes.com/dp/walkthrough.php

I'm sure someone would be more helpful than me,but here is a walk-through that I quickly looked up.

http://www.psypokes.com/dp/walkthrough.php?part=1