I dated an Italian guy for 5 years and after eating his family's traditional homemade sauce for so long I can't understand why anyone would eat jarred sauce. That said, if I'm in a rush and don't have time to make it, I'll buy whatever looks good and add stuff to it.
I like the Bertolli's organic's too and usually add grilled eggplant, or zucchini. I'll add some tomato paste, roasted garlic, and chunks of fresh tomatoes. Occassionally, I'll eat it straight up but that's rare.