I just didn't like the super lazy badge engineering GM used on the G3 (Chevy Aveo), G5 (Chevy Cobalt), Torrent (Chevy Equinox), and Vibe (Toyota Matrix). I can understand why Pontiac went away, as I see no point in having a duplicate vehicle in the same company. After all, this is the reason Saturn went away.
The only 2 Pontiacs that I actually liked at the end were the Grand Prix and G8. While the Grand Prix was based on the same chassis as the Chevy Impala, at least it had a unique design.
I also don't see a need for GMC, since each model is just a Chevrolet clone.
As for Buick, I really don't care if it stays or goes. They do have some fresh designs and have raised the level of luxury, but I will always associate the brand with old folks. I don't see myself ever owning one.
Honestly, the only GM I was sad to see go was Saab. They were just so unique.
Other GM cuts include Oldsmobile and Hummer.