Kunga guest house is really good. I stayed there for a week and am sure that will stay there in my next visit. Rates are very good and the people there are nice.
On the ground floor they have a fantastic restaurant which is known for its food quality. In the restaurant there is a small library too and you get free wifi internet there. Typically good crowd frequents this place and its easy to find like minded people there.
If you are going to visit the main monastery every day, be ready to walk a lot, as Kunga is situated at the other end of the town. Or you can rent a bike too. But on the other hand it is very conveniently located nearing the bus stand, main square and TIPA and main market. They have variety of rooms there ranging from 200 rs to 1000 or more. I opted for a room with bathroom and was quite happy with it. It had a lovely view of the valley too.
Nick's restaurant is a gem and I landed up eating there everyday even tough there were cheaper places around. One thing you should not miss is the Tibetan Massage. It costs around 500 rs and its just incredible!
Lovely place with nice people make it a place where I would want to stay again!