I guess exposure would have been more easy if you had excluded a lot more all black sky from your composition. And I believe the lights would have looked better if you had used an ever smaller aperture. Which might have mean you'd have to expose for a lot longer, but I think light sources look better when they don't turn into bright blobs but retain some shape (depending on the diaphragma of your lens, they will get starry shaped this way or that way).
I did shoot this almost wide open (f/5.6). It's the kit lense, and it hunts a little if you don't open her up all the way. I was actually shooting most of the night at around f/16, but for some reason (probably because it was getting cold), i cranked it open a bit for this one. It was like -15 deg C after all ;-)