I just saw this post and wanted to apologize. I live here and had I seen this, I could have given you some additional advice as I live here and have for 9 years. Next time you come this way, hit me up and I'll give you the 411!
As for the rest of you, all confirmed. The metro here is quite good compared to other cities. The cab system is on the zone system. The more zones you cross, the more it costs, but if your driver takes you in a big circle to get from point A to point B, he is only allowed to charge you for the shortest route zones. This only applies to DC cabs, though. If you are in a VA or MD cab, they use a meter. If you take a DC cab out of DC into VA, you'll be negotiating the fare since the zones don't extend past parts of Arlington. And, lastly, DC has just about every cuisine in existence but you might have to dig a little deeper to find the same in Va, but most are there too - just more widespread. For future reference, digitalcity.com is a great resource. Just check the 'cities' best' list.