Dunya, on Beijing East Road, has been the long-term default expat hangout in Lhasa — a Dutch-Tibetan-run restaurant downstairs and a small bar upstairs. The food is the more reliable Western kitchen in town: pasta, salads, soups, decent steaks, generous breakfasts.
The upstairs bar is the closer thing Lhasa has to a traveller pub — a handful of imported beers, single malts behind the counter, and a knowledgeable Dutch owner who will tell you which roads to Everest Base Camp are open and which are not. A good place to find trekking partners or compare permit notes.