I use a jabra bluetooth headset from a very very long time now.
As Satish asked - has it been proved whether talking on the phone is distracting ? It works as a sedative for me. I drive calmly but when I am on the phone with my gf / friends, I tend to drive cheerfully. It calms me down amidst all the traffic jams and confusion. (If its a business call - I tell them I am driving and call later at leisure

)