I'm curious, will it be just you moving to the area? If you're looking to take advantage of the city on the weekends/evenings you should live in the city. Using public transportation works great IF You use it during rush hour. If you plan on utilizing it during off peak hours it's an absolute nightmare.
I decided that space where I lived didn't matter as much to me because the city was the amenity I was looking for when I moved down here. Now, If I had a family it would be completely different...I"d probably sacrifice 2-3 hours of my day so that they'd have better quality of life, better schools etc.
The final thing you should consider are the hours you'll be expected to work, by the sound of it, if you're asking about commute times to Constitution you'll be working for the government and the majority of those positions offer flex hours or work from home options which many people utilize to make their commute easier. If you're forced to work 8-5, and you plan to live in Fairfax or Annandale, that's at least an hour commute. (or more... the biggest issue with DC traffic is that it's always bad, and then even worse when you least expect it)
Whenever people ask me this question I always throw tell them to think about what they enjoy doing, before they ask someone what they should do. It's not a black and white question.. Depending on your answers to the following, it's then about your personal preference.
- What are your hours going to be like?
- Do you have flexibility to work from home
- Do you need a lot of space? Do you have a lot of "stuff"
- Do you prefer amenities of the city, or a yard of your own?
- Is traffic something that gets under your skin... it affects some people differently than others.
- If you drive, don't underestimate the cost of tolls, and parking. It can easily cost you 50 bucks a day.. especially if you use the beltway (Check this out). It also fluctuates, and can cause unneeded stress because of its unpredictability.