Milton's Satan as Horror Movie Icon...research

Yesterday I spent hours watching movies and taking notes for this paper: Constantine, The Prophecy, and Angel Heart (which by the way is two hours of my life I'll never get back). Today it was The Witches of Eastwick and I've had a couple of thoughts:

• Angel Heart and The Witches of Eastwick are both based on books, which I had initially counted out from my criteria. Now I'm wondering if I need to go back and reread the source material and see if the film maker created an original portrayal of Satan, or if it's in the book.
• At the start of this, my original idea was to analyze the personality, look, rhetoric and function of the character in each film. After sitting and watching films yesterday, I still think this is the way to go, but now I think I also want to look at how these characters function as pairs- so Mortenson and Stormare for instance. 
• I realized when I was finished watching and taking notes today that actually few of the movies I chose are "classic" horror films. So, I went to IMDB out of curiosity to see what genre they put them in. Almost all of them were fantasy/horror/thriller. So, now I'm thinking maybe I need a pair of "classic" horror films to balance my argument out. My original intent was to choose a variety of films, but was shocked to realize that there are few horror films that actually include the character of Satan. Demons, Satan Worshipers, Witches abound, but Satan doesn't make many appearances. The one I'm looking at is Prince of Darkness.
• I can't find a copy of Mister Frost, but I have geek friends looking. Let me know if you know where I can get a copy.

So, research stage is good, and as with all great research, some great questions have been raised as I go along.
Go I wish I knew in undergad that you could make a living doing this...