We arent gonna know it until Q3, considering their new announcement policy. I think this announcement policy is slowly killing the Wii sales in Japan, because people arent anticipating anything and shift attention to other consoles. We have the top 15 most wanted titles for Japan, and it's been ages since there's a Nintendo game there. And there's only 1 Wii game, MH3 .
Not indicative of sales, but showing that Japanese arent anticipating anything Wii related

Probably in E3

I'm hesitant to believe this, if only because we already have so many confirmed motion plus games with release windows locked in. There could be a total delay of all those titles, but i don't see it happening. Nintendo will have hell to pay if the 3rd parties have to push all their titles back, or cut out motion plus support. Nintendo's in somewhat of a bind in this case

I would go with Pikmin 3 and the Retro Studios project, myself. Possibly the Factor 5 games, if F5 still exists.

I'm gonna go on record and say Pikmin 3 will be their big Holiday title.

I do not believe in a new Zelda or Mario in 2009. Usually Nintendo announced such a huge game more than a year in advance to its release. I´d think about Wii play 2, Wii fit 2, Kid Icarus, Mario Party, Pikmin 3 (which has already been announced), a new Donkey Kong or a new franchise. I expect a new F-Zero or Pilotwings as well, but they´re no major holiday titles for me as F Zero sales on the N64 and GC were not that huge.

edit: After last year´s "flop" Wii music they´ll probably think carefully about what they´ll release as major holiday title.

Mario & Sonic at the Olympic Winter Games - For sure
Pikmin 3 - Possibly
Zelda - Maybe
Mario - Maybe
Pokemon - Maybe
StarFox - Not sure
F- Zero - Not sure
Kirby - Not Sure
Kid Icarus - Not likely
Donkey Kong - Not likely

Kirby Wii
Pikmin 3
Mario Party 9

Zelda.

Yes, I also think Pikmin 3 and Kirby, not so sure about Mario Party 9 because Wii already have Mario&Sonic for the holidays.
I never played Pikmin, is Pikmin 3 a real BIG chritsmas title? I definately think Animal Crossing and Wii Music weren't .....

Zelda. I fully expect them to have other titles, too. I also think Pikmin 3 will be out, and possibly(more like hopefully) a Star Fox or a F-Zero sometime during summer, fall or winter. Nevertheless, we're sure to be able to make a more educated guess once E3 comes around.