I'm not DC-based, but for transcons, it's worth keeping in mind the Alaska nonstops DCA-SEA and DCA-LAX. You get no reciprocal elite benefits except priority boarding on Alaska, but you get full AA miles, including elite qualifying miles. I find flying Alaska as a nobody, I get service about as good as an American Gold (i. e. better than any other legacy airline). I'm on the SEA-DCA flight for the first time in January; anyone else with experience?

When I fly to DC, Dulles is very inconvenient and National is great because I get around by Metro, so I'm happy that option is there.