Certainly not national, but in enough cities to be listed here rather than the DC Baltimore page.
CAMERON'S SEAFOOD offers terrific prepared seafood at reasonable prices. Their fried ultimate platter is enough for two hungry 'hounds, and only about $15. After being gouged for half the quality/twice the price in Ocean City (Bahama Mama's), I have an even greater appreciation for Cameron's.
I know where dinner is coming from tonight.