Books
New and second hand books are available at several places, and a store with one of the best selections is located in front of namche hotel.
Handicrafts
The main street into the village is lined with tibetan run handicraft stalls and stores. most of the goods are available in kathmandu, but certain woolen items are made locally. also, check for anything special that has been carried over from tibet.
Necessities
Namche has some well stocked, albeit a little expensive, stores selling such things as batteries, basic medicine throat lozenges, aspirin etc, toiletries, sun block and trekking clothing/equipment. these items except for the trekking equipment are available further up the trail, but the variety is far less and the prices much higher.