First year was Zelda. Second year was Mario Galaxy. Third year was--er---nothing really (They brought out the big guns early with Brawl and Kart so...Animal Crossing...I guess? *shrugs* It sold well.)  Fourth year was New Super Mario Bros. And now....this year.
Unless I'm missing something, so far the contenders seem to be:
Donkey Kong Country Returns
Kirby's Epic Yarn
 
Nothing seems to stand out. Both are returning and smaller franchises. Is this it? Do you think there's something more? Do you think they've got their hopes on one of them to sell pretty well? Or do you think they're just putting some less popular stuff out to give breathing room for 3rd parties (Epic Mickey/Goldeneye) by pushing Zelda up a year?

Rumor has it that Nintendo just doesn't know at this moment whether or not the 3DS will see a holiday 2010 release or not.
 
I am guessing that is why the focus on the summer right now.
 
With the christmas release of Wii Party they will swim in money either way. 

From first party it will be Wii Party.  From third party, I hope it's Epic Mickey, but it will most likely be some dumb mini-game collection.
 
I really hope DKC Returns and Kirby's EY does good for them this holiday.

DKC Returns, Kirby's EY and Wii Party. Metroid: Other M will probably get pushed back to the holiday season, as well. No idea what will be released from third parties.

Probably DKCR 
 
There's a pretty big legacy behind it. 
 
But beyond that, I think Nintendo is looking for Goldeneye and Epic Mickey to be big sellers for the system.  Hence why they showcased them during their event at E3, especially Epic Mickey.

" Probably DKCR  There's a pretty big legacy behind it.  But beyond that, I think Nintendo is looking for Goldeneye and Epic Mickey to be big sellers for the system.  Hence why they showcased them during their event at E3, especially Epic Mickey. "

donkey kong is back!!!