I bought a TechnoTooth from Pedro's Garage.
TechnoTooth
Apart from a bit of a wiring issue (my car apparently has a later-model factory radio) that was quick to fix after 3 minutes on the phone with Pedro, the install went very smoothly. The device integrates with the existing radio and gives Bluetooth connectivity. It also includes a microphone to route up to the visor area for hands-free calling.
I know this is a product that has been around a while and has probably been discussed before, but I am very happy with the product and the after-sale support. The ability to stream my music via Bluetooth, in addition to nav and phone calls, is a great upgrade, and this was a very cost-effective way to get it done. I just didn't feel like pulling the head-unit and dropping an aftermarket system in. I've done plenty of that, and just preferred not to here.