Oh yeah, Greg is great in his areas of expertise. His book, Relativism: feet planted in thin air, is a great resource for understanding moral/ethical relativism and how to respond to it. Here is a great vid based on the book:
Frank Turek and William Craig are also great apologists. There is currently no one that I know of on par with Craig in terms of debating scientists. Praying the Lord will raise up worthy successors to these men a faith.
Phil Fernandes is the president of the Institute for Biblical Defense, and his main specialties are defending the historical Jesus and talking about the UFO phenomena. You can find him all over YouTube.
Dr. J.D Mitchell runs both Creation Engineering Concepts and the Institute for Creation Science, the latter ministry I filmed presentations for almost two years for. After seeing a number of his presentations and reading his books, I've come to have a lot of respect for him. You can check out his website here: http://www.creationengineeringconcepts.org/ics/