Xian Foods - Pictures and details on the Albums - Flushing's Chinatown.
Xi'an Famous Foods is worth the long trek down to Flushing, Queens. And their best items travel well too - the cumin lamb burgers - though be aware that the appetizing, hot, spicy smell of the food pervades the subway, the bus, and car, so make sure it is wrapped well!
Their original location is in Flushing, Queens, New York.
And now they have multiple locations in the city too - mostly downtown, in and around Chinatown: 67 Bayard St is one location. All the locations are quite small, with very little seating. And it can go from empty to crowded in seconds. Think standard NYC hole-in-the wall type of place, with great food.
[2012 Update] So the Bayard St location is good to go to if pressed for time, since going to Flushing takes the whole afternoon out. But - it seems to me that Spicy Cumin Lamb Hand-Ripped Noodles has far less lamb in the NYC location than at the Flushing location! Next time around, I plan to get the Spicy Cumin Lamb (Plate) which is all lamb, and a side dish of noodles (they don't have rice on the menu).
The Lamb Cumin Burgers are outstanding in both locations. If you take them home, sprinkle some lime juice on them, to kick up an already excellent dish another notch!
After another trip to Flushing, can confirm that food is better there. In addition to the small underground Golden Mall stall, they have full restaurant two blocks away at 41-10 Main St. They label it as a chic version of their original restaurants and have renamed it to biang!. It does look really nice. If walking from the Train 7 Flushing station on Main St, 41-10 is around 3-5 blocks down, and 41-28 Golden Mall location is another 2-3 blocks down.