I'll definately gonna get it, I'll be able to have a Ho-oh and Lugia on my (soon to be) Platinum game.

I have a horrible feeling that we'll have some roaming Pokemon in the game.
Now with Lugia, Ho - oh and maybe Celebi, they'll be 485 Pokemon you can get if you own the main series games and you go to no events.

Now that there's the DS, they'll have more stuff in it. They managed to get quite a bit on a GBA game but the DS can have so much more. A larger Mt. Moon, Viridian Forest...and others.

I'll bet that Entei will be in the Cinnabar Volcano (which for some reason disappeared!)