This big eyed cutie pie will definitely find a spot in the hearts of most trainers. It and its evolutions, Bayleef and Meganium, are perhaps the best looking of the three starting pokemon.
However, looks isn't everything. If you want to prove your toughness and pokemon training ability, Chikorita is the way to go. With a weakness against the first two gym leaders, who carry flying and bug pokemon respectively, you will need to level up a lot before being able to move on in the game. Having Chikorita on your team is a hit or miss, as it will either be really strong against a certain type or pretty much useless. Be sure to carry an electric and water type along with you if you start with Chikorita.
Luckily, to help you with the challenge, Chikorita is the best starter pokemon in terms of defense stat. You will be counting on Chikorita to simply outlast its foes early on. Also, having Chikorita on those long surfs and cave tripsp filled with water and rock pokemon is very useful.