Cornbread is eaten with vegetables, soup, or milk but never with meat. It can also be enjoyed with butter and sorghum. If you're eating at home it's ok to crumble cornbread in your soup or in your buttermilk. It's also permissible to crumble it into your pot liquor ( juice from your greens ).
Biscuits are consumed with mashed potatoes, rice and gravy, grits or with a meat. Leftover biscuits are enjoyed with butter, syrup, preserves or honey. Biscuits should never be served with vegetables - that's why cornbread was invented.
Spoon bread is considered a dish unto itself.
White loaf bread is generally served with BBQ and at fish fries when grits are available.
Hush puppies are paired with seafood and sometimes with BBQ, hash or Brunswick Stew.
A complete southern meal will feature both cornbread and biscuits. My mother baked a cake of cornbread every day of her life and always made scratch biscuits on Sunday.