If you were a TV producer, what would be the premise of your first TV series, and who would star in it?
One of my own books, obviously, and I'd have to choose based on what seemed to be likely to "hit" at the time I was producing. If I felt the Supernatural Investigation route still had some life in it, Jason Wood gets a turn onscreen. For him I get Matthew Gray Gubler. For his soulmate and eventual wife Syl, well... it might be typecasting, but I think Jennifer Love Hewitt, the Ghost Whisperer herself. Verne Domingo would be something of a more difficult choice.
If a good star-warsy Space Opera would be a better choice then either Demons of the Past, or Grand Central Arena. Sasham Varan from Demons would need someone very dark -- Indian, Middle-Eastern, etc. I'm not sure who I'd choose; the guy who played Ardeth Bey in The Mummy and The Mummy Returns is one possibility but he doesn't look dark enough. For The Eonwyl I'd need someone like a young Sigourney Weaver. Shagrath... hmm. I'm not sure. He has to be a big guy with presence, though.
For GCA I really am not sure about most of the actors; I actually envision GCA more animated than live action.