Hey there,
I've been using my iPod Nano 2G in my car for a few months now and LOVING it... my only worry with using the ipod was that the display at night was a little F-ing bright and there's no brightness control...
So I am giving Rockbox a try and so far, it's pretty awesome!
The only thing that I'm missing now is whenever I turned the ignition on in my car, the radio would come on and when it came on the ipod would go back onto charge and turn itself on, and then when I turned the ignition off, the ipod would pause the playing song and after the time-out, turn itself off...
If someone can show me how to get rockbox to do that, I'd be totally sorted :-)