Saturn's independence made it great. It didn't really threaten the rest of the GM lineup, it fostered great recognition for itself, and like O.C. said, no one knew it was part of GM. Some still don't today.
Saturn had the chance to truly exist mostly by itself, falling back on its parent for experience, engineering, customer financing, marketing budgets, and warranty assistance.
I really don't see how Saturn is going to fare from here on out. They sold just as well with three bodystyles of one vehicle as they did with six bodystyles of four vehicles. Its no longer the friendly, happy lil' car next door; now its apparently going to be some svelte, sophisticated car, some half-assed Oldsmobile if you will. You have to understand the place Olds once held in the American marketplace as a truly desired and intelligent automobile. Only Olds had identity, history, and a following in that genre; Saturn doesn't.
Plastic panels, free car washes, the Saturn Fest in Spring Hill, and all the other aspects of traditional Saturn culture is fading. You and I may make fun of it and write it off as some dorky goofball shit, but so many people bought into it and loved it.
And most importantly, they bought the cars, too...
Will they now?