It depends on the way you see it. In terms of Pokemon you can catch, emerald is just like a mix of sapphire and ruby (not combine because some Pokemon like Roselia cannot be caught in emerald that can easily be caught in sapphire) with a little of leafgreen and firegreen (after elite four you can get shuckle, mareep .etc in safari zone)
Fire red, Sapphire, or leaf green
the best Pokemon region is hoenn { ruby,Sapphire,emerald }
The best starter Pokemon in Emerald/Ruby/Sapphire is Torchic. If you level it up well, it'll sail you through the first 3 gyms with ease.
The strongest dragon type in pokemon Emerald, Sapphire and Ruby, is the legendary pokemon Rayquaza. In terms of non-legendary pokemon, both salamance and flygon are strong dragon types.
Green
raquaza is a master legendary Pokemon in emerald ruby and Sapphire. his is most likely to be the best Pokemon in the series (Case in point)
I would say the one on the way to de-activate the generator at new mauville near the cycling rode in Ruby, Sapphire, and Emerald.
go to Google and search Pokemon sapphire pokedex and it will give you a list of all the ones you can catch, you can also search for a national pokedex and look for treeko and that is the beginning of the sapphire/ruby/emerald pokedex(heres a link of the best one ive found sofar ... http://Lloyd.truepath.com/Jonathan/PKMNRS_Pokemon.htm ... ) go to Google and search Pokemon sapphire pokedex and it will give you a list of all the ones you can catch, you can also search for a national pokedex and look for treeko and that is the beginning of the sapphire/ruby/emerald pokedex
it madders which game . ruby: groudon, sapphire: keyoger, and emerald: rayquaza. but if you did not catch one of themm when your suppose to your beginner Pokemon at it's final evolution.
You can't catch staryu in firered only in leafgreen or ruby or sapphire or emerald.
the best pokemon to use is mudkip.
the best way is to buy ruby and sapphire or emerald