Nowhere in DC is safe. At work, I lock my bike in a garage that has valet parking and building security. Even in this seemingly low-crime environment, every bike on the rack lost rear wheels except for me in one 12-hour span about six months ago.

NY-Chain around the rack, frame and rear wheel. Mini-U around the front wheel and frame. The chain stays at work and the mini-u/cable combo travels in the bag for quick errand stops.