Over the years I've owned a number of power extender devices but I've never really used them because more often than not they have always been a big heavy slab of battery. A few weeks ago I bought one of these Power Monkey devices originally because I'd bought a new device at the airport and wanted to charge it before I got to my destination. The PowerMonkey comes pre-charged to 60% which is really handy if you are about to get on a plane or have a device running low on charge.
Over the past few weeks I've found I am using the PowerMonkey more and more - mainly because it isn't a massive brick of a battery and fits in my bag quite neatly. It also comes with chargers for a variety of phones, iPod and also a MiniUSB charger. It comes supplied with international plugs for about 150 countries so it makes it really handy to carry.
You can check out and buy the PowerMonkey HERE