Temperance Hall is a bar and restaurant in the Petworth neighborhood just a block from the Georgia Ave./Petworth Green line Metro stop. It has quickly (it opened in Jan. '06) become the "local" for Petworth residents. The food is American pub fare that some interesting twists. There are a number of options of vegetarians including excellent crispy eggplant and fontina cheese with fuji apple sandwiches. The draft beers feature a rotating selection of small, independent craft breweries from the States and abroad. Currently I enjoy the Wolavers Brown Ale and the German Kolsch (brought in especially for the World Cup this summer).
If you like Wonderland in Columbia Heights, give Temperance Hall a try. You may end up making it your local as well.