New Trent is one of the best brands of external battery packs out there. I own the previous version of this 7000mAh one from them. It's been phenomenal. It has two USB ports, one that outputs at 1A for phones and one that outputs at 2.1A for phones or tablets. The new version also has a short, built-in microUSB cable that can be used instead of the ports, as well as a built-in USB cable for charging. I went with this one because it offered a perfect balance of what I needed - the ability to recharge a phone 2-3 times on a single charge, a higher power USB port for larger devices, it's relatively thin and light, indicator lights to tell me how much of a charge it has left, and it charges with a standard USB charger (there are several out there that use a proprietary charger, and it's a pain to have to carry around yet another cable when traveling).
There are many other external battery packs made by New Trent with varying sizes (both in terms of charge and physical size) with varying price points, and they all have stellar reviews on Amazon.
I got this one on a special for $23 on a one-day special at Daily Steals. It's a 10,000 mAh battery pack...yeah, I said 10,000 mAh, or 10 AMPS! It's awesome. It charges my Droid RAZR MAXX phone (with the 3,300 mAh battery), at least 3 times- sometimes 4 depending on what point I connect. It also has two ports - one for the 1.1A and one for 2.2A. It comes with two short microUSB cables but unfortunately they don't work with the RAZRs, so I just carry my stock cable along with it.
I have a solar powered charger that has a key chain attachment on it haha. It's the size of a ketchup packet with a 2inch connection cord. By no means the greatest thing ever but it has saved me a couple times (when the sun is out).
Indeed it is. I'm often away from electricity for extended periods of time, so I'm always on the lookout for new external chargers that fit my needs. But I have yet to find one that balances power, size, and features as well as that one from New Trent.
What's nice is, now I can sit in the bar all afternoon and not have to worry about running out of juice- period. And I got rid of my Smartactions that I had set up to dim the screen. Now I just leave it at about 75% all the time.