As a developer for iOS, Android, and Windows who also teaches their programming, I have all the major iDevice models ever released. (But, naturally, I don't have the different storage / 3G / color configurations in one model.)
As I always carry many of these iDevices with me, I also need at least twice the number of cables. Let's also take into account that Apple's own cables have a tendency to break apart and the need increases even more. Just Google, “iPhone cable breaking apart”; and you'll find threads with pictures such as this and this.