It's interesting that most of the mobile phone manufacturers have backed a plan to create a common charger. One of the reasons iPhones and iPods are so dominant is their integration. How many car stereos have you seen with integration for another manufacturer (and I don't mean MP3 connections, but ones you can control from the head unit), or speaker docks that support other platforms without another cable?
I've long wondered why the rest of the MP3 (and phone) manufacturers don't get together with some manufacturers to draw up a spec for a port so everyone can have a standard and then all benefit from accessories and integration. I can only assume it's politics.