This is the one I came in to mention. Oily and slimy and leaves a bad taste in your mouth!
If there was any movie I was less surprised to find out that it was being made up on the spot…it’s “The Prophecy”
…and supposedly (If I remember correctly) Viggo wrote most of his own dialogue, and they filmed all his scenes in one day. I love that S***. How cool. I show up, write my Devil lines, and after one day…I’m done.
This is the one for me. Pacino finally gets to play a character hammier than he is.
I’ll cast my vote for Milton’s Satan. He’s a complex and not completely unsympathetic character.
Beautiful. Satan is a self-loathing entity in the unbreakable grip of brutal depression.
Another vote for Peter Cook here: “Just putting a tiny little ventilation hole in this oil tanker…”
I have a soft spot for this one as well, though.
Peter Cook is my hands-down favorite depiction of Satan by an actor and the mailbox scene is one of the greatest scenes ever filmed.
I’m also fond of Jack Chalker’s demon in And The Devil Will Drag You Under.
And someone mentioned Jerry in Heinlein’s Job, which rocked as well.
I like the Bobby vs. Satan sketch from Kids in the Hall (starting at 1:45 in the video). This is the 1980s variety Satan as depicted on heavy metal albums.
I’ve always been fond of the Devil as depicted in The Devil Went Down to Georgia by Charlie Daniels.
the devil jumped upon a hickory stump and said: "Boy let me tell you what:
"I guess you didn’t know it, but I’m a fiddle player too.
"And if you’d care to take a dare, I’ll make a bet with you.
"Now you play a pretty good fiddle, boy, but give the devil his due:
“I bet a fiddle of gold against your soul, 'cos I think I’m better than you.”
the devil was just another good ol’ boy with an ego.
My first thought was Rowan Atkinson’s Satan from A Warm Welcome.
Then I thought of Heinlein’s Jerry from “Job”, as have several others upthread.
And although he wasn’t Satan per se, I think Crowley from Pterry & Gaiman’s “Good Omens” deserves an honorable mention.
Count Iblis from the original Battlestar Galactica.
For those who don’t know, “Iblis” means “Lucifer” in Arabic.
I almost listed that
I’ve never seen Charlie Daniels live, but my friends who have say he performs the devil’s part of that song so awesomely, they all think he needs to change how it ends. 
Mick Jagger’s characterization of Ol’ Scratch in “Sympathy for the Devil” is equally brilliant. He’s so polite: “Please to meet you…” Axl Rose does a fair job, too.
Twain’s narrator in Letters From the Earth. One of the funniest things ever written.
Twain’s narrator in Letters From the Earth. One of the funniest things ever written.
Al Pacino, Devil’s Advocate.
Peter Stormare, Constantine.
I always like Burgess Meredith’s portrayal of the Devil (in that Twilight Zone episode).
This guy made a dying small town newspaper big-in exchange for the soul of the owner.
The 1944 film “The Devil and Daniel Webster” was pretty good too.
I like it when people get the better of old scratch.
DeNiro in Angel Heart. Very creepy