I agree with dinner at Fish Market in Old Town. They have great raw oysters.
As for breakfast, Silver Diner (chain) which has great pancakes or for dim sum, New Fortune in Gaithersburg. Although it is somewhat of a hike but not too bad (1/2 hr), they have more variety and is pretty good (as opposed to Fortune in Falls Church).
The Prime Rib is also great but pricey and you have to dress up in suit/tie as someone mentioned already. I’ve tried many of the dishes from steaks to salads and they are all good.