Having gotten a new iphone 4S last month, I had been keeping it in a white apple bumper (that I'd used on my white 4 before upgrading)
It's an older bumper, so the buttons didn't line up correctly, and it was looking a little, well, dirty.
Got this cheap from amazon:
Not overly impressed, but it's doing a job until payday at the least.
I'd replace that USB cable.