I couldn't agree with the last reviewer more, Mughals is not only a great place to eat in the Sanlitun - Nali Patio area (top floor), but the food is fresh and affordable. I especially like the rooftop at sunset although the decor inside is comfortable and homey.
On to the food..
What I like most about the food is that it is authentic in taste but lacking in the copious amounts of oil usually found in Indian food. In other words, it's Indian fare for the health conscious. Each curry is cooked separately meaning that a lamb curry tastes substantially different than a chicken curry (as it should). The garlic nan is to die for and the samosas shouldn't be missed. If you're a desert person, try the kulfi - you won't be disappointed. The owner and his wife are almost always in the restaurant providing quality control and pleasant conversation.