In my old car (which didn't have line-in) I used the Griffin iTrip Auto:
http://www.griffintechnology.com/products/itripauto/
Which is a pretty slick FM transmitter. Now that I have the HCH I've switched to line in, which produces a nice static free ride. I should be happy, but I miss three things about my old iTrip:
- Charges while listening, my iPod always had a full battery when I arrived at work.
- Automatic pause when you turn off the key. I listen to a lot of podcasts and find my self desperately grabbing for the ipod pause button after parking so I don't miss anything.
- Normalized volume. With line-in you have to crank the iPod volume way up, and me (being a forgetfull sort of guy) end up blowing out my eardrums later in the day when I stick in my earphones and press play. Youch!
It looks like the solutions below offer some of these these features, do either of them do all three? Is there something that does?