I had the pleasure of visiting Stockholm twice this summer for business. On both trips, I could not get enough of this restaurant, B.A.R., near the Grand Hotel. Despite its location in the middle of tourist central, this is a gem that is quite obviously enjoyed by both visitors and locals.
The concept is so relevant: The family-run business focuses on local, seasonal, fresh produce to enhance what is already a visually stunning experience. While there is a heavy emphasis on seafood (this IS Sweden!), vegetarians or meat eaters will be equally thrilled with the selections. B.A.R. offers full menu service, or you can go to the ice counter to select your own piece of fish or meat to be cooked to order. If you don't feel like dining out, they also offer to-go or just take-away (and cook yourself) options.
Also, do not miss the cocktail and beer menus—further examples of the creativity and emphasis on simple, fresh, tasty ingredients. My favorite was the Cloudberry Kir.
While nothing in Sweden is cheap by U.S. standards, a dinner here will not break the bank. And it will be worth every penny.