Let's get down to it:
Chevrolet
Beat/Groove: three-door (Beat) and five-door (Groove) replacements for the Chevrolet Aveo based on Gamma II.
Cruze: Delta II-based with a coupe bodystyle added to the recently revealed sedan.
Malibu: Epsilon II-based sedan. (Coupe on SWB EP-II?)
Camaro: Alpha-based 2+2 sports coupe.
Corvette: becomes lighter, more efficient.
Trax: Gamma II-based crossover SUV.
"Blazer:" Delta II-based crossover SUV; replaces HHR.
Equinox: Theta II-based crossover SUV.
Traverse: Lambda II-based crossover SUV (rename Tahoe?).
Suburban: receives a moderate mid-cycle enhancement, Tahoe dropped (rename Traverse to Tahoe?).
Silverado: receives a moderate mid-cycle enhancement.
Colorado: Total redesign.
Buick
Regal: Delta II-based sedan.
Riviera: SWB Epsilon II coupe.
Invicta: LWB Epsilion II sedan.
Enclave: uses a short-wheelbase Lambda-II platform and only seats five.
Pontiac
Tempest: Alpha-based coupe and sedan. (Redesigned Holden Torana.)
Grand Prix: as Holden re-engineers the Commodore to be more fuel-efficient and lighter, the G8 will simultaneously receive the same updates; it will also transform from its current incarnation of G8 into a brand-new Grand Prix (or Bonneville) with its own specific exterior and interior.
Solstice: Kappa II-based roadster and targa-top coupe.
GMC
Sierra: receives a moderate mid-cycle enhancement, which further differentiates it from it's more "work-oriented" Chevrolet cousin into a more user-friendly, but still capable, pickup.
Yukon: the Yukon XL takes the regular Yukon name as it is phased out in favor for the Lambda II-based Acadia; receives a moderate mid-cycle enhancement to further differentiate it from the Suburban.
Acadia: Lambda II-based, seven seat crossover SUV that is a further evolution of the current generation model, replaces current standard Yukon.
Terrain: Theta II-based crossover SUV.
Saab
9-3: Delta II-based three and five-door premium compact car.
9-5: Epsilon II-based sedan and wagon.
Cadillac
BTS: Alpha-based sedan, wagon, and coupe.
CTS: in it's next-generation, it will use a premium version of the redeveloped Global RWD architecture (Holden Commodore) and will have coupe, sedan, and wagon versions.
DTS: uses a long-wheelbase version of the premium GRWD architecture and will be positioned as the flagship Cadillac with standard premium smallblock V8 power.
SRX: Alpha-based crossover.
Escalade: CTS-based, seven-seat crossover.
XLR: becomes lighter, faster, more efficient.
SaturnSaturn dies and is replaced with Opel. Opel inherits Saturn's independent dealer network and expands it with more stores in additional key locations, but not so many as to have excess dealers. All Opel models come to North America.