Her car does not have bluetooth, however I got her this. I didn't realize it had that ability built right in thats awesome! She's not against using voice commands so hopefully I can teach her how to reply handsfree.

My car is weird about bluetooth (it only does phone calls), so I've strongly considered getting that HTC Bluetooth Clip thingy. But, to be honest, I'd probably go with something like this Belkin Bluetooth Car Kit (currently $44.79 on Amazon). It hooks up to your aux input and you transmit your music to it via bluetooth. The only downside is that you wouldn't get track information like you would with connecting directly to your stereo via bluetooth.

On a side note, I do have the Belkin Bluetooth Music Receiver (currently $20.09 on Amazon). It's the same concept but for home use. I have it hooked up to one of the inputs on my receiver, and any of my bluetooth-enabled devices (HTC One, iPhone, MacBook Air) can connect to it. It's super convenient!