A few I can think of:
Albania - Ismail Kadare - I've read all of them in French, however not all are available in English and IIRC the English version is translated from the French rather than from the original in Albanian
France - Lautreamont was missing from Istvan's rather good list
Japan - Kawabata, Inoue, Abe, Tanizaki and a few more for the classics
Lebanon - Amin Maalouf
Algeria - Malika Mokkedem - not sure what is available in English though
Egypt - Naguib Mahfouz
Italy - Italo Calvino
Pakistan - Tariq Ali (the Islam Quintet)
Hungary - Sandor Marai, Magda Szabo
Peru - Mario Vargas Llosa
Portugal: Jose Saramago
Morocco: Tahar Ben Jelloun