Mr. Qi is right that you should go to Bianyifang, which enjoys high fame in Beijing. I have had dinner with friends at the Chongwenmen Branch of Bianyifang last week. The duck was very good and much cheaper than Quanjude which is said to be the top one and requires extra service charge. We have 5 people together and booked two suites of ducks, including two ducks, four baskets of thin pine-cake with four seasonings for each. The total fare is 280RMB. If you just have one or two people, you could book a half of duck which just sold 59RMB.

You could take the subway Line 5 and get off at Chongwenmen station. Go out from the Exit C, you will see a red brand of China Merchants Bank, which is located on 1F of the New World Department Store. Please enter into the store and take the elevator upstairs to 3F where the restaurant is located. The restaurant is opened from every 11:00.

For another Chinese food, there are lots of snack restaurants distributed in Beijing. I have found some not far from the north gate of the Beihai Park. Starting from the norht gate, please walk westwards to the first crossroads, where you could find several good restaurants. And, some time-honord Beijing restaurants have set their braches along the Qianmen Street, such as Daoxiangcun with good dim sum.