During the summer Trädgården is the place to be if your out clubbing. It has a great festival atmosphere. The chance of you getting seperated from your friends is immidiate but you will meet new ones. I have a love-hate relationship with this place, watch out for the massive que and the ill willing pointers.
This is a great spot for lunch or coffee! In the summer you can sit outside. They have a beautiful botanical garden and is located next to Brunnsviken (lake). The also have a huge greenhouse with plants from allover the world.
It's been at the same address for the last 80 years apparently and serve some classic swedish food like köttbullar and isterband. Being swedish I guess could I either avoid or cherish this, but I choose the latter.
If you want to try something outside the city center this is a really beautiful small gem. They cook delicious seasonal food and have a nice selection of cheese and charcuterie for your wine. Best to book table beforehand.