im surprised no one mentioned Star Ocean 4.
or is that one not a favorite?

Well they did say a 360 favorite.

Could be any of the shooters.

Surely its Viva Pinata !

If we're considering the arcade route I wouldn't count out a port of Castle Crashers either. It definitely qualifies as a favorite, and Behemoth haven't announced platforms yet for their third game which could mean they're beginning to work on PS3 as well.

The article also said that the studio itself would have other big news, and lots of game 3 info could qualify...

you wish xD

Maybe its Ace Combat 6, it is a Platinum Hits now. Maybe that is there criteria

Geometry Wars.

Has EA dismissed L4D? No? Then it's still a possibility.

ok, I've been looking up to find out if epic own the Gears IP, and judging from the button quote it seems they do but they have a publishing deal with Microsoft which makes it exclusive.
The quote is from 2007 and the source link will is below:-

""We've shot down this Gears of War on PS3 idea about a hundred times already," said Rein in an e-mail to PSXE. "Microsoft is the publisher of Gears of War. Unless Microsoft wants to publish it on PS3 then it won't be published on PS3.""

http://www.psxextreme.com/ps3-news/1541.html

After having read that, I can assume that it is possible that Gears 1 could be it, hell it could also be mass effect 1, or just some online game going to PSN like Braid as people have mentioned....I guess the whole point of that announcement was to create discussions amongst forum people of what it could be, in other words hyping something that in effect doesn't exist to the masses.

They said '360 favorite'. That leaves only 3 possible games for me : Gears, L4D or Mass Effect.