For me, I'm wantin':
- Spore (already been watching this for a year now). It already had a large number of gameplay and technical elements at GDC '05, and it has had a year since then for refinement. I don't think it is really safe to judge this kind of game by anything short of a demo or full product though, but the potential for something cool is definately there.
- Supreme Commander (Been watching for about a year as well). I'd really like to see some video of the game in action - thinking of those screenshots in motion with the description of having entirely physics based combat gives me chills. And I've just been disappointed be every single RTS made after Starcraft. It would be nice if someone would finally make one that's actually improves on it in areas other than UI and graphics.
- And most anything made by Nintendo and its children (Zelda, Metroid, SSB, Mario)