...In the end, we can expect see 2 mainstream versions: the next generation Astra to be sold under the Opel/Vauxhall/Saturn banners and the Chevrolet version that will be sold in world-wide markets.
There are other possibilies as well; some confirmed, some implied:
A new G5: IF and WHEN it makes it to market, it will only be a placeholder as Pontiac moves toward RWD. Otherwise, I don't expect to see Pontiac making much use of this platform.
Buick Skylark: It is slated to be sold in America and supplant the Buick Excelle in China. We know that the Skylark will replace the Excelle from an
Edumund's InsideLine Story and it was more than implied it would make it to North America as well.
Saab 9-1: This is the vehicle that will create added volume for the Saab brand and give GM a legitamite competitor to vehicles like the A3, 1-Series, C30, et al.
Next Chevy HHR: When the Cobalt is replaced, it will obviously mean either the HHR will need to be replaced eventually or phased out. The recent popularity of the HHR and of "crossovers" in general will probably mean a 2nd generation of HHR will be making it to market.
The Chevy Volt: GM's wunder-car is supposed to be built on the Delta II platform; another important product riding on this architecture.
Article: HERE