Hellmann's Mayo/Best Foods Mayo - Best Foods Mayonnaise is sold in supermarkets west of the Rockies, while Hellmann's Mayonnaise is sold east of the Rockies.
Edy's Ice Cream/Dreyer's Ice Cream - Dreyer's Ice Cream is sold in supermarkets west of the Rockies, while Edy's Ice Cream is sold east of the Rockies.
I wonder if anyone else knows of any other regional food brands...