One of my favorite films is "Cast a Deadly Spell." This 1991 made-for-HBO film is a combination of 1940s detective film noir and "magic is commonplace" mentality, and it just strikes me as a perfect setting for the Majus games *I* wanna run.
Never heard of the movie? You're in luck as the entire film has been posted to YouTube.
Enjoy! (Click me!)
Howard Phillips Lovecraft (Fred Ward) is a private detective living in an alternative America in the 1940's where creatures thought fictional coexist with humans in a society where magic is real and practiced on a constant basis. Short on money, Lovecraft accepts a job from millionaire Amos Hacksaw (David Warner) to recover an ancient tome called the Necronomicon. Unbeknownst to Lovecraft he has stepped into a complex web of lies, deceit and murder. He is also mankind's last hope at repelling an ancient evil that if unleashed will mean the end of civilization.
(There was a sequel titled "Witch Hunt" starring Dennis Hopper as Lovecraft, but I haven't been able to find it just yet...)