We were at the Hyatt Arlington for 4 night, in early March. The room was good, and we got it for $85 a night through Priceline.com. The desk staff dowstairs was very friendly and efficient.
Just around the corner is the Rosslyn subway station that takes you directly into City Center or the other way to Arlington or the Pentagon. Can't beat a location like this!
There is parking underneath the hotel, and it seems to fill up quickly. Other parking is available behind the hotel as well.
We were on the 6th floor and could hear some noise from the outside, but nothing to be a disturbance - it is a city after all.
The unpleasant thing about this hotel though was the girl manning the "coffee shop" downstairs on Monday through Wednesday, when we were there. She had the personality of a doorknob and was very unpleasant to customers, including ourselves. On the other hand, the girl there Sunday morning was lively and efficient. An real attitude readjustement would be in order.
I highly recommend this hotel.