I don't think this person counts exactly as the steriotypical preacher but I found his two series very informative for Christians. His name is Mark Fairley and he has the "Know your Enemy" and "Fuel Project" series on YouTube. There is one episode specifically on Jehovah's Witnesses from the Know your Enemy series that is well done. They were worth the watch for me as I gained a lot of good knowledge and encouragement.
Francis Chan was already mentioned but I like him also. Great energy and love for God.
Shawn McCraney is interesting. Seen a few of his shows and they are low key down to earth and aimed at helping Mormons to come to Jesus.