I think a small startup in Israel has just made Google maps on smart phones obsolete (along with every existing GPS manufacturer).
Waze - a social navigation tool that uses your position and speed to detect traffic conditions and alert your fellow travellers in real time (and it also allows you to share info about accidents, police traps etc.)
Honestly Google - how did you miss this one? Google maps is installed on every Android phone, but you can't use it to give us real time traffic? I understand that there are privacy concerns, but that hasn't stopped you with anything else :)
If the ability to share traffic information with your fellow commuters was not cool enough, it also lets you update the street maps in real time either from your smart phone or via the web.