Now that the law in California requires drivers to have their hands on the wheel (if they are over 18) while using a cell phone, hands free devices are becoming the preferred choice for people still addicted to driving and talking. I've been using a blue tooth for years, but find the quality of the sound fluctuates from fair to poor depending on traffic and wind noise, not to mention the reception in certain parts of town.
If you want the best over the ear device, the Jawbone uses something called VAS (Voice Activity Sensor) to distinguish the difference between when you are talking (there is a small bump over your jawbone to "read" when you are talking) versus when there is noise in the background. The military actually made a smart move by using these in their wireless communications, and PCWorld named Jawbone a "Best Buy".
If you are only using your blue tooth in your car you can switch to the BlueAnt Supertooth 3 which not only allows you to call, but also answer the phone via voice command. The beauty of this device is that it stays on your visor, so you don't get the annoying ear buzz from over the ear models. An added feature that this device incorporates is a caller ID that speaks the caller name (from your telephone address book), so you know who is calling without having to look at your phone. Parlez-vous Francais? Pas un probleme, this phone speaks six languages.
Both these devices cost under $100, which is much less than paying for tickets (and yes they are ticketing cell phone offenders), but they will give you easier and clearer ways to communicate, which is after all the point of cell phones in the first place.