My family stayed at the Embassy Suites Alexandria Old Town a couple of years ago. The metro station is across the street.

There's a Hilton in Arlington which is situated directly over the Ballston Metro stop; the Garden Inn near the Arlington County Courthouse is within sight of the Courthouse Metro entrance; there's a Holiday Inn as well as a Westin (I believe) within three blocks of the Ballston stop; those various hotels in Rosslyn including the Hyatt and the Marriott Key Bridge are within easy walking distance of the Rosslyn stop; there are a BUNCH of hotels within walking distance of the Crystal City stop including a Hampton Inn, two Marriotts, etc.

The Ritz Carlton sits atop more or less the Pentagon City stop.

I stayed at both the Lorien and the Hotel Monaco in Alexandria on recent trips. They are part of the Kimpton chain and very nice. The Lorien is within a very short walking distance of the King St. Metro stop and a free trolley serves the Monaco. I loved staying there because it was quieter than DC, but gave me very easy access. Lots of restaurants and shops, plus the lovely waterfront in walking distance of either property.

Have fun!

The Loew's L'Enfant Plaza is on top of the Metro station of the same name, but that is about all that I can say good about it, though I have enjoyed other Loews.

Check out www.LastMinuteTravel.com website. I have booked hotels thru them and had a friend get a room in Arlington, VA this past Oct. When you access the Washington DC area listings, the first hotel in the list is the Sheraton Pentagon City (formerly Sheraton National Hotel). It is listed for $127. for April 8th date. You will find the hotel much higher priced on other websites. We loved our stay there, we had a very spacious room w/ 2 queen beds which were on 14th floor overlooking the city and Arlington Cemetery. They have a free shuttle that would take you to the metro station daily and also dropped us off at the nearby mall. Very convenient location. Think you would enjoy your stay there. The restaurant was not cheap so you would have to plan accordingly to feed your family. If you are driving, there is an underground garage but they do charge for parking.

http://www.roomstays.com/hotel/583754

We usually stay at the Embassy Suites in Alexandria . . nice rooms, right across the street from the King Street Metro Station. Easy walking distance from Old Town Alexandria

http://embassysuites3.hilton.com/en/hotels/virginia/embassy-suites-alexandria-old-town-WASOTES/index.html

I used LastMinuteTravel once also and the hotel I got was the one I determined it was before submitting based on the photos. I have seen it recommended a lot on TripAdvisor

Another recommendation for The Lorien in Alexandria. Absolutely lovely.