Transmitters for MP3 Portables?

kwerle writes "I have just received my new iPod, and am now faced with the issue of how I should hook it up to every stereo I own. For the car, I could just get one of those cd-to-cassette converters, but that just doesn't...feel right. What experience have you had with mp3/cd player transmitters (like this one from Arkon or the MK-90)? Any suggestions?" Don't forget about the iRock Update: 04/24 07:46 GMT by C : Errors in the URL for the iRock have been fixed. My apologies.