DCA has Cosi which is pretty good, but Five Guys is awesome. I'm just waiting for In'n Out to make it way to the east coast in some airport, and that'll be the end of my medical. Another good one is in RIC, there is a cranberry and pear chicken salad topped with almonds and goat cheese at some vendor that is to die for. Honestly, it's some good stuff. Also if your stuck in LGA, outside of the airport, if you walk across the bridge towards the La Guardia Airport Hotel, there is a food truck in the parking lot with a great (i.e. spicy as heck!) prime rib sub that is only 5 bucks. In Boston, do NOT eat from the Au Bon Pain Express that is mid way in the US Airways terminal, it's awful. I had a tuna melt that had been sitting for what seemed like days, and I had the toilet shots to prove it the next day!