Viper is gone. Too Niche. Vette outsells the Viper by a larger margin and has a very long heritage to go with it.
My takes
Cobalt/Caliber Cobalt cause of the funky styling of the caliber
G6/Avenger G6 only because it's sales are so much greater
G8/Charger Charger stays. Chryslers upcoming platform will be better then that of what will underpin the G8.
HHR/PT Cruiser HHR PT's styling is long in the tooth.
Vue/ Patriot. Hope they're both gone. Maybe something can be made in a new name to fill that spot.
Traverse/journey Traverse the new Lamda platform is superior.
Tahoe/Durango Sorry but the Tahoe stays. Durango sales are too slow.
Silverado/Ram Ram will hang around only thanks to Nissan. Chrysler is under contract to supply the new Titan based on the upcoming Ram. After that say good by Ram.
Colorado/Dakota. I say Dakota goes mainly due to slow sales.
Hummer H3/Wrangler. Kinda hard to compare. Personally I see Hummer going away and seeing the H3T renamed as a Jeep.
Camaro/Challenger Camaro because of the platform and engine choices.