I had a new Motorstorm pegged in for a holiday release this year, but it turned out SCE Liverpool are deeply involved in the 3D tech, so might not be working on a title at the moment.
Insomniac will likely have Resistance 3, or a new IP for the holidays.
Eat Sleep Play, Media Molecule and Lightbox Interactive may all have titles in the works that could release this holiday season.
I don't think there will be a lack of exclusives, just in an unusual turnaround the 360 seems to have most of it's lineup shown, while Sony are remaining tight lipped about their own.