Ovechkin got my vote but sort of like Ali, I haven't had much of a favorite DC player outside of baseball since Peter Bondra left. I was crushed when he left DC because I grew up watching that guy.
The Redskins haven't had anyone worth cheering for awhile, the Wizards are, well, the Wizards and the NBA sucks, and unfortunately I haven't kept tabs on DC United enough to have gathered a favorite off the team (although I really should).