[pedantry] The National Gallery isn't actually a Smithsonian museum, although it has a free-admission policy as well. [/pedantry]

As others have already pointed out, DC's dining scene is rather lame. There *are* some good restaurants, but they're far outnumbered by mediocre, overpriced places.

If you like Ethiopian, try Ethiopic on H Street NE, or Dukem on U St. NW. As already noted, Ethiopian food is basically the only ethnic cuisine that DC proper does well. Otherwise you have to trek out to the burbs.

Also, shopping in DC is flat-out bad. There's very little in the way of local flavor. Most of it is mid-market chain or mall stores, with a preponderance of stores (e.g., Ann Taylor, Jos. A. Bank) selling boring clothes that Republican lobbyists would wear to work. Georgetown has a bit more in the way of variety - but honestly not much. If you want to shop, there's always Pentagon City Mall in Virginia - reachable quite easily by Metro.