Stay longer & visit Nusa Menjangan in the north (best snorkelling on the island) before heading across the straight to Java. In Java, do the midnight hike up to Kawa Ijen (volcano) & see the blue flames (gas burning inside the crater), plus the beautiful sunrise. Then go to Yogjakarta for the most famous sight in Indonesia, Borobodhur. And finish your holiday by flying out of Jakarta.