i absolutely agree that if fm transmission is a possibility then we should be able to use it without entering the dang matrix to free it. i agree that in rental, work, and friend's vehicles it would be wonderful and impressive. i ALSO agree that for navigation, handsfree calling, and apps like those, fm transmission would be acceptable.
i just know that when it comes to music, fm tranmitters are sub-par. one guy said that his for his ipod sounded fine. with my old ipod i compared 4 different tranmitters and the very best one still didn't come close to pluggin into an aux. it might be fine for you, but to me the word "fine" is not acceptable for a $550 device that has such great sound. music wise, i have compared the droid to the samung omnia, the lg envy touch (with dolby sound), and a microsoft zune (with flat eq). i turned down the "media volume" 1 notch to compensate for the clicking/popping issue and the droid STILL smoked all those devices at full volume!!!!
i know i don't speak for everyone, but i spent good money and signed another 2 year deal for this thing. i want the absolute best this phone has to offer, and settling for fm transmitters in MY car would be a shame. keep in mind that i do sound for a living (live, studio, bands, voice overs, etc. etc.) so i might be a a lil too "elitist" about the sound thing, but to me, it's heartbreaking to hear my favorite music sounding like it's being run through a 1980's boom box. i believe an extra $100 on a new deck for my car is a worthy investment considering you can find one that also does bluetooth.