[Nexus One Accessories] attn1:
FH-P8000BT with integrated Bluetooth/external microphone. No Bluetooth adapters to buy. Mine was $230.00 delivered, prices have gone up slightly since I purchased.

Amazon Link

I am posting this because I know there are lots of people having big trouble with certain Bluetooth devices and the Nexus One. While this setup isn't perfect, it's seems to be working better for me than many people are experiencing with factory car Bluetooth installations, particularly in Nissans.

I installed a new head unit in my car today. I didn't have any way to play MP3's in the car, and I wanted to remedy that, and figured why not get something with an integrated bluetooth solution for phone and audio as well while I'm at it.

I picked a double-din Pioneer FH-P8000BT (with built in Bluetooth, but with an external microphone). It's no high end unit, but it has a decent amount of features for the price, and gets good reviews.

Amazon had it for $230ish, delivered.

Pros:

Pioneer syncs bluetooth for both music and phone with Nexus one.

Once paired initially, the Bluetooth connects automatically when the vehicle is started.

Bluetooth audio quality is much better than I expected for Bluetooth.

GPS NAV voice directions work well over car speakers with Bluetooth connection. This is welcome, as the Nexus One's built in speakerphone is not the greatest.

Phone has priority - incoming call switches to phone mode automatically, muting whatever else is playing.

Pioneer microphone for hands free works reasonably well. Typical muffling of outgoing phone audio.

The PAC adapter for steering wheel controls works reasonably well.

It's rated at 50W RMS, which I am sure is bull, but it's still punchier than the stock radio.

Being able to place the external microphone is a real plus compared to having a microphone built into the head unit. It allows for better placement, and since the mic uses a standard mono mini audio plug, it would be a cinch to replace with another to try to improve the sound. But it's unnecessary because the supplied mic works acceptably.

Cons:

Edit: I was able to finally sync the address book - with lots of persistance. Once synced, it retains the info and you don't normally need to resync each time you connect. Syncs fail most of the time.

No Radio preset buttons. You can scan between presets, but nothing resembling an old fasioned push me and go directly to this channel button.

The menus are less than intuitive - for example you have to read the manual to figure out how to set the clock unless you venture a very lucky guess.

There doesn't appear to be a way to shut the radio completely off. Edit: There is, by pressing and holding a multifunction button. There is no dedicated on/off button that is illuminated, which was the source of my initial confusion.

No bluetooth or radio voice dial capability.

Sometimes playback control through the head unit is lost, even if streaming is still working. If I reconnect, it comes back most of the time.

As I said, this is a lower end unit, so maqny of the cons are really a lack of features because I cheaped out. My biggest beef is the address book not syncing reliably - that really should just work. Most of my other complaints are about lack of controls, but what's there works pretty well. I've gained a lot of good functionality, it sounds good and overall, I am happy to have it. Hands free phone and music with plenty of volume and no cords is very nice. I have a car charger in the event I need the NAV. Now all I need is a good bracket to car mount the phone, and it will be a pretty complete solution for travel.

Note: I am using cyanogenmod 5.0.5.3, and have tested with stock ROM. You're BT experience may vary, especially if you're running something else.