I think Zelda for 09, SMG 2 for 2010...
All of those titles are great, but they would leave the Wii without a real heavy hitter.
I will say Zelda for 09 until Nintendo makes it clear it wont be.
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut