Johor Bahru is the state capital of the state of Johor and the second largest metropolitan area in Malaysia. Most tourists don't stop here and just pass through the city on their way to or out of Singapore. JB is a major local transportation hub however. Since it is just across the causeway from Singapore, some travellers use it as a hub to visit Singapore from here (lower accommodation prices) or to board the train, bus or airplane.
Tiny state in Borneo, sandwiched between Sarawak and Sabah. After it was a big regional player a few hundred years back, Brunei became rich upon the discovery of Oil in the 1940s. For a period time the Sultan of Brunei was the richest person in the world.