"At your momma's" is usually the best, but you might try one of these if "your momma don't live here no more."
Domilise's - uptown joint on Annunciation, if you savor the authenticity
Parran's Po-Boys on Vets is near the Second Serve Tennis shop...they'll restring your racquet while you enjoy a poboy
DiMartino's - roast beef, Italian sausage and Swiss on the westbank
Chubby's on General Meyer has great fried seafood but unusual hours of operation
Parkway Bakery - Bayou St. John location
Casemento's oyster loaf is unique if you find yourself on Magazine, but not in the summer
Mothers - uses cabbage, near the river on Poydras is a favorite with tourists
Johnny's - lunch stop in the CBD in the shadow of One Shell Square
Parasol's in the Irish Channel (one block off Magazine Street at 2533 Constance) famous for St Paddys day celebrations
Russell's Short Stop on Transcontinental near Airline
Salvo's - best oyster poor boy, Belle Chasse
Maspero's in the Quarter near Jax Brewery can be fun and touristy
Central Grocery on Decatur has a muffaletta if you like your sandwiches in the round
Radosta's just off Metairie Road offers a grilled shrimp poboy called the Joan Special
Bear's Metairie Rd location under the Causeway overpass has all the PoBoys
and amazingly a convenience store, Danny and Clyde's offers exceptional overstuffed poboys at locations in Metairie, Mandeville, Houma and Thibodaux. Brother's is in this hunt as well for best convenience store chow.
and about 5,000 other locations around the city. Comment if you love one.
(Subway and Quizno's have found their way into town but their sandwiches do not qualify as poor boys because the bread is all wrong. )