It seems like every year post 2007 everyone says the same thing Microsoft doesn't have that many exclusives lined up for the next year. Microsoft likes to play things close to it's chest they don't let people know about all of their games 2 years a head of time.
I am possibly excited for
Kingdom under Fire 2
Project Kingdoms (crytek game)
Forza 4
Gears of War 3
Also I think mistwalker was under contract to complete 3 ips for the 360. Blue Dragon, Lost Odyssey, and Cry on but Cry On got cancelled. Hopefully they will make and complete a 3rd ip and release it on the 360 after they finish with the Last Story on the Wii.
I am not worried Microsoft usually has good games each year for me to play and if not there are plenty of quality 3rd party games to play.