I don't have a Bold but I ordered today this model : BlackBerry Premium 1.8A Micro-USB In-Vehicle Charger for PlayBook which should not only power your Bold but also a PlayBook at the same time in case you have one.
I can only tell you later this week how good this charger works but it comes with an integrated cable and an extra USB receptacle.
Since I also use the BB music gateway in my car this extra port comes in handy because one less wire to untangle
when the phone is present.
http://ca.crackberry.com/blackberry-premium-18a--micro-usb-in-vehicle-charger/5AA11480.htm
This site also offers car chargers at less costs for BB phones but also with less features. Have a look here.
