1) Deadskins will always be #1 in this town. Even when they suck, the local sports media has endless drama to talk about. Even though the NFL product has diminished over the years (I stopped watching because it's boring), there are many diehards clinging onto past superbowls (last one was almost 30 years ago).
2) Capitals - thanks to Ovi, the arena typically has high attendance. I see more people around here wearing Caps than Nats gear (top notch scientific study). Think the Caps have pulled fans away from the other local teams.
3) Nationals - With so many games and some of them going 4hrs. It's not easy to get people to go and stay at the games and watch people play chess.
4) Wizzers - Yikes. My friend has season tix near the bench and go a few times per year. I went to a game last year. Low attendance and I almost fell asleep. Unless Lebron etc is in town, there is no reason to attend unless you want some 'personal time' with your partner.
5) DC United - I think the games are fun: People are singing, banging on drums, and lighting smoke bombs and fireworks. However, local sports media rarely mentions them unless it's they're in the playoffs.
6) Mystics - Make it stop