Since I live in Finland it’s easy to go to Sweden with a ship that costs about 50 euros go and back and lasts about 9 hours if I remember right. Stockholm is a very nice looking place, you get that old Scandinavian feeling there in the old town. I go there sometimes when I just want something different.
You can see photos from my Sweden flicrk page
This is just one of the ships that go to Stockholm from Helsinki.