The Makye Ame in my opinion is one of the best restaurants in Lhasa.
It serves mainly Nepali food, but also has some Western, Indian and Tibetan items on the menu.
The interior is friendly and warm as is the staff and if you sit by the window you can watch the pilgrims go by on the Barkhor.
The food is excellent and the shakes can only be recommended.
This is also a great place to do e-mail or relax on the sofa and read one of the many books available.