Planning trip to Wash. DC mid August - need recommendations for moderately priced (approx
$300/night) hotel/B&B/VRBO?condo, etc...traveling with my wife and 11 year old...preferably located near easy public transportation into area of capital

I used to always recommend the Dupont Circle neighborhood, because it's got lots of restaurants and is pleasant to walk around and has a Metro station; but now I tend to suggest Penn Quarter instead, because it is within walking distance of many Smithsonian museums and the National Mall, AND offers lots of dining options, AND gives access to several Metro lines.

Search here for other threads on DC--someone gave an excellent rundown of the Kimpton hotels in the city and the pros and cons of their locations and amenities.

I'm a fan of Penn Quarter too.
I find Embassy Suites to be a good choice when traveling with kids and there is one at 900 10th Street NW, just on the northwest edge of Penn Quarter. If their rates are within your budget, that would be my recommendation.

Here's the thread NewbE is referring to:

http://www.fodors.com/community/unit...-in-dc.cfm#top

We stayed at Woodley Park Guest house and found it a lovely spot with a Metro station just half a block away and lots of restaurants nearby. The front porch should be pleasant in summer.

Another endorsement for the Penn Quarter area, for all the reasons NewbE cited. And as you look keep in mind that in mid August DC weather is basically a swamp, so look for something with a pool!

The Embassy Suites longhorn refers to is really nice. Any hotel in that vicinity that fits your budget would work well, I think.

Couple of years ago we stopped in the Georgetown Suites in the Georgetown area and found it a reasonable price and an easy base to start from. 25 min pleasant walk along the river to the bottom of the mall and a good bus service into the centre. Also there was some lovely shops and restaurants in the area.

I found myself and my husband in DC six years ago-- the week after we got married-- when I was asked to speak at a conference. We stayed at this hotel in Foggy Bottom:

http://www.theriverinn.com/

All-suite boutique property, a short-ish walk to Georgetown, two blocks from the Foggy Bottom Metro stop. The neighborhood is more residential than you'd expect for being right off of K Street, but it's still in the middle of everything, and the hotel itself was great (it looks like it's holding up). I would check it out.

Our friends and neighbors rent this wonderful basement apartment in Dupont Circle: http://www.vrbo.com/186865

My husband and I stayed there for a few weeks in February when we were flooded out of our apartment. It's beautiful, and the neighborhood is hard to beat. It's about a 7-minute walk to the Dupont Circle metro stop, and there are cafés and restaurants and shops galore all over.