On the island Penang. A not too big city with history, many beautiful architectural buildings, good restaurants and nice hotels. And an interesting mix of Indian, Chinese and Malay people. Penang even has very nice beaches. See my posting about Chinese Shophouse Penang.
2. Malacca (Melaka)
Again not too big city and with a beautiful history of colonial buildings. Nice shopping, good restaurants and some Dutch history (eh .. stolen Portuguese history). See my posting about Chinese Shophouses Malacca.