I honestly would look into getting a new car stereo with a line-in jack. I’ve tried all of the FM transmitters and it seems like no matter which one it is, and no matter what the cost, you still can hear the radio static in the music. And that gets annoying really fuckin quick.
I’ve got a Pioneer stereo in my car which does not have a line-in. Pioneer makes this special little Ipod adapter which charges the ipod and sounds incredible. The only problem with it is once you plug your ipod in, you have to use the car stereo buttons to control it, or unplug the ipod, pick a new band/song, and plug it back in. Its a good idea in that it keeps people from changing tunes on their ipod while driving, but its kind of impractical because its a pain in the ass to change songs while driving. Catch 22 I guess.
A stereo with a line-in is what I’m working on acquiring the funds for. You get perfect sound without any extra noise and you can control you ipod as you normally would, with the little scrolling deal. The only down side of the line-in junts is that they don’t charge the ipod. No loss, you could just charge it at home like everyone.
Those are my thoughts on the subject.