GoalZero Guide10 Plus
This is a handy little battery pack to use with other Goal Zero products. The main benefit of this is that it will charge a device whilst it's being charged from the solar panel - that makes it an ideal 'buffer' to keep a higher current device charging during patchy sun (or even a device which needs more current to charge than the charger can deliver). Most of the other battery packs you'll see on eBay or from Deal Extreme use a similar group of chipsets and will not charge a device whilst they're being charged.
The Guide10+ also uses the slightly higher wattage dedicated port on the Nomad panels, which means it makes better use of the panel.
Being able to charge AA or AAA cells is another useful differentiator for this battery pack.
There's links to more battery packs on this page.
WIll it charge my iPhone 4, 4S, 5? iPad etc.
Yes, it will charge an iPhone 5 from 0 up to 100% and then from 0% up to about 10%.
I tested this with a fully charged set of the supplied batteries, from the phone having shut itself down with no power, up to 100% in flight mode and then back to 0 and up again. So you can expect to get at least 1 full charge from the battery pack.
When I originally received the Guide 10+ I found the supplied cells were not holding full charge. I had to recondition them using a good battery charger (a BC900) first in order to get them back up to full capacity. Full capacity in this case was around 2200mAh per cell.
With the batteries all charged to around 2200mAh per cell I was able to get the full charge from the Guide 10+, before that I had real problems getting even a 50% charge from the device.