[EDIT] Sorry dbot, I didn't notice that you posted almost exactly the same thing as I did above me. 
The article said that the "studio" also had other exciting news to share soon. Therefore, I would take a guess that it is a large company, and therefore would rule out arcade titles made by small developers like Braid, Castle Crashers etc. Looking at the Microsofts big hitters, I can pretty much take a guess and rule out that it won't be Halo (though, IMO PS3 owners arn't missing out much with this one). Gears of War series I think is too important to Microsoft to let go and so I would imagine they would make sure the previous titles stay on the 360. As has already been said, Mass Effect is a possibility and to back this up their other exciting news might also be the fact that Mass Effect 2 will be multiplatform. Saying this though, I find it hard to believe that Microsoft would let such a big title fall away from them... but you never know, with EA they might not have much choice.
Left 4 dead I can't realistically see Valve (the studio) being suddenly that friendly toward the PS3 judging by its previous comments. Dead Rising is a possibility, but consideing that the PS3 is already getting Dead Rising 2, it's doesn't exactly match the statement "getting a 360 favorite" as PS3 owners were getting the sequal anyway. There are a other games such as Crackdown + 2 which might be a possibility, but it would just be guess work. Therefore, at this stage i'll probably be leaning toward Mass Effect + 2 going to the PS3. Still, we won't know until they announce something...
I think I am with a previous poster who said he hates announcements of announcements. Don't bother saying anything until there is something to say.
