I saw A.D. a few years ago on television. It was the only series/film about the Roman empire I saw, in which the Forum Romanum was rebuild realisticly. Although it is very difficult (not to say impossible) to revive the past, I would say that the cast and crew of A.D. managed to recreate the first decades of the Roman Empire in a realistic and believable way. If one wants to learn more of the history of this period, A.D. provides a good history lesson.
I liked also the way in which the several stories are set. Not only do we get a view of the lives of the first Roman emperors and the deciples in Israel, the series also follows the lives of a few common people in these times. The mixture of these stories (although this is fictious) is very good.
I find A.D. a very good series. It is a pity that there are no reruns of the series. I understand A.D. is on VHS, but I did not find it yet (Maybe someone can help me with this). Hopefully one day it will be released on DVD. I am looking forward to that.