Travel Alarm Clock
This is the item that most backpackers forget. There are many times on your trip that you will need to catch a flight or need to be at an attraction by a certain time. If you sleep-in and miss a train/flight, it can cost a significant amount to get to your originally planned destination.
Travel alarm clocks
can come with many additional features, such as temperature, humidity, and date. Some have a world clock feature, that you can adjust to the zone you are in. All of these extra features are not really that useful. The most important thing to look for when buying a travel alarm clock, is the size. The smaller the alarm clock, the less space it takes up in your backpack.
Casio and Lewis N. Clark, both make an excellent travel alarm clock.
Casio Travel Alarm Clock