Well, good luck getting helpful responces. Thing is, different places are right for differnt people, and you're going to get people who just post about how everywhere else sucks.
Example:
I'd rather die than live in Gaithersburg, but it's better than Reston! F*** those assholes in N. Virginia.
Get it? Basiclly, most people live where they do because they like it a lot more than other places. And even though it's all pretty close togethor, there are big differences.
A lot of people don't quite understand how much things in the DC area cost. If you want to live close in--meaning a place that feels like a city, not a suburb, it'll cost a lot more than a lot of other places in the country. Thus, beware of places where prices seem a bit too reasonable for their own good, they just might be a bit ghetto.
If you want a downtown sort of a feel look at:
DC (duh); Bethesda; Silver Spring; Arligton, especially Ballston and VA Square; Takoma Park; parts of Alexandria; Friendship Heights if you have money you don't know what to do with;
DC itself is obviously complicated all by iteslf. Hopefully this'll get you started.