OK, the secret is this. I said to the family that I wanted to spend my 60th birthday in a place where there was a bit of snow and no obligation to go to a museum (don't misunderstand, I love museums...but have seen more than enough). We pretty well managed this by going to a hotel outside Stockholm, where I for the most part sat next to the open fire and worked on my book, and the family did higher cultural things just 10 minutes ride away in the city. (If you want a recommendation, it's the Hotel J and great, with brilliant views over the sea).
On New Years Eve itself, we went off to the hotel's own restaurant, ate lobster and monkfish, then went back to our room, watched a bit of Baz Luhrmann's Romeo and Juliet on the tv, then the fireworks (at the top of the post), then crashed out. (The next night was a little feast of "Lewis", plus "Celebrity Mastermind" -- what bliss).
I do reckon I missed something by not actually going in to Stockholm. The rest of the family were pretty entranced by the George and the Dragon in the cathedral, but I can wait till next time.