Hokkaido's specialties include crab, corn on the cob, potatoes, Jingisukan (Genghis Khan -- a dish of mutton and vegetables that you grill yourself), salmon, and Ishikari nabe (a stew of salmon and other Hokkaido vegetables, also cooked at your table).
Sapporo is also famous for its ramen, and the most popular place to eat them is on a tiny, narrow street in Susukino popularly known as Ramen Yokocho. Located just 1 short block east of the Susukino Station, it's an alleyway of noodle shop after noodle shop. It doesn't matter which one you choose -- just look for an empty seat. Each very small shop consists of a counter and some chairs, with photos of various dishes outside the front door. Most are open daily from 11:30am to 3am. Ramen generally begin at ¥800 for a steaming bowlful.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.