Are you asking who was the best defense witness according to the b**** d*** jurors? Or are you asking whom do I think was the best defense witness?
1) Obviously the only person the jurors truly listened to was Jose Baez. He won them over with his outrageous opening statement/theatrical performance. Anything the prosecution witnesses said was moot.
2) After that, George. They didn't trust him.
3) LE deputies who said they didn't smell any odor from the car. The jurors tossed out all the testimonies of many witnesses saying there was odor, to believe a few who said there wasn't. Never mind that those cops weren't concentrating on the car, possibly passed by it quickly, were far enough away not to detect any odor, or they had summer head colds and couldn't smell anything.
4) Of course there were all the young, clueless friends who said Casey was a great mother, an "amazing" mother. Friends who only saw her with Caylee for moments in time, not day in and day out because Caylee was usually with InvisiNanny.
5) The jurors ignored testimonies of 70+ witnesses and focused only on that of 10 or 12. Casey was truly judged by a jury of her peers. They couldn't wait to get back to their vacations and all the $$$$$ they dreamed of collecting from interviews.
If our justice system is the best in the world, the others must be horrible, horrible!