The PSP2 (or whatever it is called) may have a 3D screen or it may not ... Personally, I think the big question is whether the PSP2 will exist in a similar form factor/market space as the PSP did.
What I mean by this is that the PSP was meant to compete directly against Nintendo in the handheld gaming space and the iPod in the portable media player space; and the PSP was lacking of very important characteristics in both market-spaces as a result. I don’t think people will question how the PSP was lacking as a media device in comparison to the iPhone or iPod-Touch; but the fact that the PSP didn’t have the battery life, load times, or kinds of games that the DS had hurt it as a portable gaming device.
In my opinion, in order for the PSP2 to be a successful device Sony has to decide what its primary purpose is, make it excel at that, and then add the other features to it. If their focus is on gaming the PSP2 may have a 3D display, if it is a media device that would be less likely because it doesn’t really have much of a point.