I work in the dc/nova area, live in Baltimore. Sometimes the work is closer to or in Baltimore but I spend roughly 60% of the year commuting to and from the 495 corridor. The time you are expected to be at work makes a HUGE difference in how the commute is. 7-3. Very light traffic in the morning, moderate traffic in the evening. 8-4. Moderate traffic in the morning, heavy traffic in the evening. 9-5. Heavy traffic in the morning, even heavier traffic in the evening.

If you can work earlier hours it's not THAT bad of a commute, peak hour commutes can be hell sometimes.

If you plan on living in Baltimore living nearer to 95 will shave off 20-40 minutes daily. If you have to go through downtown or take 695 your commute will be extra painful.

Having said that I'm pretty adjusted to having a long drive every day, I prefer living in Baltimore where my salary goes a whole lot further than the dc metro area. Plus, I think Baltimore is much more fun and laid back than dc. I have a company vehicle so gas and maintenance aren't my problem, that may factor into your decision if you drive your personal car.