If you're working in Reston I think you have a lot of options. You can certainly live in Reston, which is nice enough, and not completely overpriced given the area. It's a great area if you enjoy biking. I'd recommend someplace near the Dulles Toll Road and Reston Town Center. You're pretty convenient to Dulles and not too far from areas like Tysons Corner. Probably about 45 minutes to DC without traffic.
The other nice thing about working in Reston is if you choose to live closer in to DC you basically have a reverse commute. When I go to Reston for clients or for training, it's always been pretty traffic free and have gotten there in as little as 20 minutes when coming from my house in Falls Church.
Reston generally is a pretty safe bet but too suburban for my taste. Pretty nice area though. I think Herndon is a bit too far out personally. I live in Falls Church City and like it a lot. I also like Arlington quite a bit, but it's very hit or miss depending on the area. When I lived in Oakton I had a nice apartment and felt very safe. Very sleepy and suburban, but pretty convenient too. About 30 minutes from DC and only two exits from the Beltway.
Places to avoid: I really don't like the way Centreville is turning out. Overpriced for what and where it is. Arlington is great but you've gotta pick your neighborhood wisely. I have friends off of the main drag in Manassas and that area bums me out. The older, quiet parts of Manassas are a lot nicer, but it's still quite a ways West.
What kind of area are you looking for? Hip and vibrant? Cozy and safe? Rural and private?