Hi Everyone! I've been reading posts on this site for about two weeks now (since I got my Moment).
I've had the same problem with the Bluetooth not reconnecting reliably. From reading posts, I learned that the problem was only after power-cycling or going in and out of Airplane mode. I tested my theory and found that if I set my phone to "discoverable" for the 120 seconds, my car would redetect the bluetooth; even long after the 120 seconds was over. My car would keep reconnecting to bluetooth every time until I power-cycled or went in/out of Airplane mode.
I set out to find some more info on the bluetooth problem and found this information on Google's Android site, http://sites.google.com/a/android.com/opensource/projects/bluetooth-features.
For some reason the wording, "Support for auto-pairing with '0000' devices" in the Android 1.5 feature info caught my attention. I had been setting a more complex code for pairing between my car and phone. So I re-paired using the code 0000 and I haven't had a bluetooth pairing problem since!
I've power-cycled and gone in/out of Airplane mode several times since and my car has connected to my Moment every time. I know that not every bluetooth device can use a custom code, but I hope this might help someone.