Take the following devices and try and work out what they have in common.
1) Nokia "throw away" PAYG phone
2) Apple iPod Touch 3G
3) Apple iPod Classic 160 6g
4) Minirig portable boombox
5) X-mini portable speaker
6) Garmin GPS
And the answer is they all charge from +5v, 500mA. But they almost all use a different charging cable and/or a different sync cable.

In fact in total, I need 2 Sync cables and 4 charging cables to handle all of that. How did it come to this? This is why there is an EU directive that all such devices should be abble to be charged via Micro-USB socket. Except that the only device that has one of those is the Nokia and that can't charge from USB. And Apple only support this directive in their latest phones via a Micro-USB <-> Lightning connector. Even though I hate it, I do kind of understand why Apple does this and why they think they're special. And of course they can get away with trying to get you to spend extra money on genuine Apple accessories. But what's everybody else's excuse? And that's before we start adding in Android phones, iPads, tablets and other devices that charge from 5v but need more current than the standard USB 500mA. Or the new USB 3.0 connectors.

Can we please just sort this all out because I'm sick of it.

1) Nokia throw away PAYG phone
No charging via Micro-USB. USB is only for sync. Charging uses their small tip as opposed to the old 3.5mm large Nokia tip. Their nominal 5v charger is actually 6.5v. They'll happily charge from 5v but then won't report charging complete, battery full. 

2) Apple iPod Touch 3G
Will charge from any old USB charger with an Apple sync cable. But won't charge from a custom charger aimed at supporting Apple's enhanced USB not quite standards aimed at supplying > 500mA

3) Apple iPod Classic 160 6g
Will only charge from an Apple charger with a normal USB sync cable. But will some times charge from other people's chargers depending on the smarts of the charger and of the cable. Won't charge from a Computer or USB hub unless the computers is on.

4) Minirig portable boombox
Requires it's own USB lead as they use a 6mm plug.

5) X-mini portable speaker
Charging and line in/out on a mini-USB. Hooray! Except that the built in audio jack lead always breaks, so you need the combined USB-Jack lead or a jack to jack AND a USB-mini-USB.

6) Garmin GPS
Charging on a mini-USB. Hooray!

This rant is because I've just bought this 4 port USB charger, to discover that while I only need to carry one plug, I still need a pocket full of leads. Grrrr!
http://www.portablepowersupplies.co.uk/portapow-quad-usb-uk-us-eu-mains-charger/