Just like the earbuds that ship with iPods and iPhones, the Apple USB cable isn't meant to be the highest quality item to come out of Cupertino. Apple does a lot of things right, but their cables and earbuds just don't cut it.
We depend upon our cables so much yet pay very little attention to them. At least until they fail. I plug and unplug my iPad so much, to ensure it is always charged, that my cable started to fray and fall apart. I could replace it with another identical cable, but for under $20, I figured I'd rather have the DuraLink from the Joy Factory
The aptly named DuraLink
is rugged from tip to tip, USB to 30 pin, and all along the 4 feet in between. They offer longer and even very short cables, great for traveling. The cable is made of a flexible, durable material that resists tangling and just feels superior.
If you need a cable, either as a replacement or a spare, consider upgrading to the DuraLink from the Joy Factory