I have lived in the Clarendon/Courthouse area, now in Rosslyn, and moving in a week to Ballston. We looked a lot around Old Towne recently but the commute for me would have been way too much. My wife goes against traffic so it isn't a concern for her.
At 25 you should consider your social habits. If you enjoy hanging out with friends or going into DC to socialize, I am not sure I would go further out than Ballston on the orange line or further south than Pentagon City/Crystal City on the blue.
Most twenty-somethings are hitting Clarendon up hard lately. Expect to pay 1000+ for a studio, ~1500+ for 1bd, ~1000 for 2bd with roommate. Most singles share places. Consider this too...if you live within a mile of metro, price goes up b/c its considered walkable. If you can metro to work, do it. It really is that simple. Parking will likely be astronomical.
My wife and I just spent a couple of months looking for our new place so feel free to ask questions if you have them. As Plano said it'll seem expensive no matter how you shake it.
If all else fails check out the green line....probably has some cheap rent.
[This message has been edited by osterhaseD (edited 6/22/2011 9:44a).]
