EDIT: i delved a little deeper on how to get all of the pokemon, and it seems you can get all the rest that are not on LG/FR and R/S on Emerald. I dont care too much about the legendaries like celebi, jirachi and mew. two questions though.

is this true? being able to get all the g/s pokemon in emerald, not including the nintendo event pokemon.

i see that Ho-oh and Lugia available through the nintendo events that seem to be long over, but, are there any other ways of getting them, other than through the events?

You can't get ALL the GSC pokemon in Emerald, but you can get the ones that are missing from FRLG/RS. You can get all of them, except Celebii, Ho-oh, and Lugia I believe.

Also, Ho-oh can be obtained from Pokemon Colosseum, and Lugia can be obtained from Pokemon XD. Besides Nintendo Events and cheating, I don't think there are any other ways to get those two birds.

thanks, that is exactly the information i needed.