I like Sturehof, it's a Stockholm classic. It's been there a long time, doing what it does well.
I often take friends who are new to Stockholm to show them some classic Swedish dishes done well in an upmarket dining environment. The service is always top notch too, with waitresses in their classic white nautical themed uniforms.
You also can't beat it as a place to sit in the summer for an outside lunch and a bit of people watching
I will be back soon.