Gears of War 2 from renowned developer Epic Games is probably the biggest one, still to be a 360 exclusive and coming this November. Next is Ninja Gaiden 2 from our beloved Team Ninja, which is set for a worldwide June release, though right now the only specific date is June 3rd in the US. Both had videos to boot, which you'll be seeing shortly.
Fable 2 has also been announced, from the mind of Peter Molyneux, which isn't just a standalone game but comes with "pub games that will be downloadable via Xbox LIVE Arcade." You'll actually be able to play that XBLA game and earn money, then use it in Fable 2, which is an intrepid idea, so long as that game has multiplayer and doesn't make us wish it was Uno.
Update on Fable 2
Update on Fable 2: there will actually be co-op in the game. Meaning you can go into someone else's world with your character, interact, do missions, leave and take whatever you earned with you, and come back to your world. Now that's awesome.
Finally, the last big one is Too Human from Silicon Knights, which we all remember had a fight with Epic Games (still having it, supposedly). Still, they weren't shy and showed off some brand new footage that looked quite spiffy. While not technically a sequel, who the hell cares? As long as it isn't released the same month as any of the other games mentioned.
What are you looking forward to the most? And don't worry, we'll be here all night long.