The track of the storm (the bisector of the "Cone of Uncertainty") shifted about 30 miles west early Thursday, but may have shifted again at 11 PM slightly to the East. The average track has the Eyewall playing tag with Ocean City MD (picture above from 2010, lower end), as a strong Category 1. There is great concern about what happens when it reaches New York City, flooding lower Manhattan, many lower areas of the outer boroughs, and causing transit to be shut down for several days.
A track slightly inland could bring stronger winds to Washington and particularly Baltimore.
The danger for homeowners in further inland areas with individualized problems is that repair crews may be diverted to coastal areas with many more widespread problems.
During Isabel in 2003, where the track was west of DC, there was widespread tree damage and outages for ten days or so despite the fact that during much of the storm winds were relatively light and there were periods without rain. It was actually pleasant outside during much of the event.
Inland, the strongest winds will be from the NE, and later the NW as the low moves away. That means the pattern of tree damage may be different from what happens in usual thunderstorms.
Weather Channel video of timeline as of Thursday night:
Here is the NBC Washington Forecast: Late Friday afternoon, predictions have downgraded the intensity of Irene slightly. It was reported as expected to be a Category 1 as it passes Ocean City.