We'll be flying in to London and staying for a couple of days before taking the train to Edinburgh, where we'll stay for 8 days. Then, it's back to London for a couple more before flying back home to the US.
Funny thing is, despite the focus of the trip being Scotland, I kept wanting to make sure we had at least 2 full days (so that doesn't include a travel in/out day) in London at both ends of our trip. After finding myself shaving off a couple of our Edinburgh days, I kept kicking myself for having done so and finally just took a few extra days off work so I can get 4 full days in London while still getting more than a week in Scotland :)
London's just too great to miss out on! Though I'm certain Edinburgh will be fantastic, as well.