I'd have to say, the PokeWalker and Pokemon traveling with you

The sinnoh pokemon of course.

I would definitely agree with James, but I'm also quite excited for the new touch-screen controls, the updated graphics, and some of the other smaller details.

Which reminds me, although I wasn't able to play more than 4 minutes, I noticed that when you go by water in the Japanese game the music softens and you can hear the waves; is this true or was I just imagining this?

The new egg moves.

Johto has always been my favorite region

The MASSIVE Safari Zone! I always loved the Safari Zones, and this one should keep me entertained for a while, heh heh heh.

I'm just excited to see one my favorite Pokémon games become upgraded and moved onto the DS.

in all honesty, the arceus event...and jirachi event...and celebi event.

I am excited to play in johto for the first time.

The music and newer sprites, their so refreshing.

Flying Pikachus. That's just unreal! Then again, so is the entire Pokemon series, anime or games.

I'm gonna go with the music on this one. The soundtrack is just great for this part of the series.

I also look forward to the "Gameboy music" item that reverts the music to the GBC music.

Ah, nostalgia.

I'm one of those people who prefers the 'little things' over specific features, but if I had to pick one, it would be the excellent soundtrack. I've been enjoying it for a couple of months now.

I'd have to say... Going to Johto and Kanto.

My most favorite thing about the upcoming hgss game is the fact that you can walk with your Pokemon.

I am looking forward to pokemon following you,the safari zone, and a longer gameplay

I'd have to say the Pokéwalker, the AWESOME music, and the revamp of Kanto so that it doesn't feel like the cart almost had enough memory to support a full 2 regions.

Run Toggle Button.

and <-my Favorite I couldn't get into D/P/P