Joh,
What a fabulous opportunity. I LOVE Washington, DC. However, there's one factor for your consideration that I haven't found among the comments and tips everyone has been sending. I'm a little late joining the conversation, but if you are still weighing things I think you should take a look at the cost of living in DC, particularly the cost of housing. Other than an isolated conclave of the very wealthy here or there, DC is THE most expensive place in the country to live. If you haven't yet, take a look at the cost of houses and condos in DC. Even with the pound/dollar rate in your favor unless there's some break on housing cost for you because of your position you might be shocked at how much of your income would be absorbed by that single item in your budget. Having said that, if you can afford it, what an exciting and beautiful place to live.