Food Network's Diners, Drive-Ins & Dives isn't often wrong... and Northern Waters Smokehaus is unique and delicious. Like a number of my recent posts suggest, you should consider stopping at this place if you're in the Duluth area. They have a nice menu of unique sandwiches, which all incorporate their smoked fishes/meats or their homemade salamis (salamii?). They appear to turn a very brisk business (it was busy), but the staff knows what their doing and actually seem to be happy doing it. It helps when the people like what their doing, a lot.
Not only is the food worth it, but the DeWitt-Seitz building that houses this restaurant also has a ton more shops, and the whole area is down on the lakefront with lots of stores and eateries. It could easily be the perfect afternoon stop on your way back down to the T-C.
This is the Northern Bagel. It's a great helping of smoked salmon and a healthy schmear of scallion cream cheese. I would whole-heartedly recommend it. They have about a dozen other options too.