Yes, I believe that cell phone use in cars should be illegal. When you are using a cell phone, be it texting, talking or playing a game you are not paying attention to the road. When you are not paying attention to the road, any sort of awful things can happen. I can think of no situation where having a cellphone has benefits that outway the negatives.
One can not say that cell phones should be banned in cars. What if the car is parked? What if it is one of the passengers using the phone? But one can say that cell phones and texting of course need to be banned when it comes to the person who is actively driving or even just stopped at a light so that others are protected.