TOD
National:
PANERA BREAD
IHOP - breakfast only
CRACKER BARREL - breakfast only
RED LOBSTER - prefer this over most other family-type chains; prefer the old kitschy decor to the current upscale-ish bland look
U.S. regional:
STEAK & SHAKE
BOB EVANS and PERKINS - breakfast only
WAFFLE HOUSE
WHITE CASTLE
BIG BOY (Bob's, Frisch's, etc.)
More local regional:
(Cincinnati): SYKLINE and GOLD STAR. Never had them frequently enough to cultivate a preference.
(NYC-centric): SHAKE SHACK. Various NJ/NY/New England diners that aren't really a chain, but they're all very much alike.
(L.A. - Oy! where to begin?): DU-PARS, MARIE CALLENDER'S, TOMMY'S, ASTRO BURGER, probably many many more.
PEA SOUP ANDERSEN'S - at least it used to be a chain. I'm forgetting a LOT here.
(Philadelphia): Don't recall the names, but several CHEESE STEAK places.