I commute (on my bike) 1 hour 15 minutes from Prince Georges County, Maryland to Old Town Alexandria, Virginia. But then again, I'm perhaps a bit wacko in that regard.

I suggest that you get an ADC Bike Map of the DC Metro Area. It has all the bike trails and the on-road bike routes. It's very helpful and will be useful as you look for a place to live (you WILL get the job...I'm confident of it!)