yeah northern va is wicked expensive.
stay out of mclean and tysons corner... too expensive to live there for most people.
during the tech boom, 1 bedroom apartments were 1,400 in alexandria, and there was a waiting list. thank god the prices are finally dropping.
alexandria is nice except for the gridlock and lack of parking, which i think a bunch of people have already mentioned. if you like artsy stuff, there is old-town alexandria - check out the Torpedo Factory (no, thats no a sexual reference). It's like a warehouse for local artists to showcase their stuff. it's on the waterfront too. it's one of my favorite places to relax, alone. there are some great dive bars in that area also. there are a few "ghetto" parts in alexandria as you get towards US1. overall, alexandria is nice, and you can go to d.c. on the weekends.
if you don't mind driving, i'd recommend living further away from d.c., like in manassas or dale city. i have friends who bought a brand new house in dale city for around $250k which would have been about $550k across the street from me (Fairfax). the good thing about these two places is that they are self-contained. all the commerical stuff is in your town - like target and TGIF. the bad thing is that you have to drive to get anywhere else.