Philly cheese steaks; a Philadelphia specialty, and no one does them better than Geno's. These sandwiches, if you can call them that, are made with steak sliced thin (steak-ums), and topped with onions, cheese-whiz, or provolone cheese. Although Philly cheese steaks are full of grease (and no self-respecting New Yorker would touch one :-)), they are satisfying after walking around all day, not to mention easy on the wallet.
Should Geno's not satisfy, you can try its mortal competitor, Pat's, located across the street.