I just got an unlikely source of inspiration for my Ars Magica campaign. It's the tv series Carnivale, and so far I've seen the first half of the first season. Despite being set in the 1930's, this series just gives me a seemingly endless stream of inspiration for stories about Divine and Infernal powers in Mythic Europe. 
Just wanted to ask if anyone else know of any other good tv shows or movies to draw inspiration from, especially for the supernatural aspects of the setting.
E.
Hmmm.. Well a bit tacky IMO but there is "Charmed" of course, which makes a very Hollywoodish attempt at presenting witchcraft and the divine/demonic fight.
Another interesting show is a miniseries called The Lost Room which might give inspiration for enchanted devices that are all somehow linked and have odd powers when combined.
Not a tv show but a very good film which might be a good source for shapechanger/lycanthrope ideas is called Blood & Chocolate.
Those are the first things that spring to mind.
Well, the main thing about Carnivale is the dark mood, and the often direct and mature way of illustrating difficult issues.
I've seen a couple of episodes of Charmed, but it's, as you say, pretty Hollywoodish and less mature. Never heard of the Lost Room, though.
Didn't see Blood and Chocolate, but isn't that some kind of Romeo & Juliet with werewolves thing?
There is another series, I can't remember it's name, as I've only seen it's cover. It's some post apocalyptic thing.. hmm.. can't remember though..
E.
The Lost Room is a 3 part miniseries that was created by the Sci-Fi channel in the US. You should find it easy on p2p share either through Torrent or DC++.
There is the Romeo & Juliet aspect yes, but it treats the subject of "werewolves" not from the typical man-wolf creature aspect but much more romantic and i believe original legendary aspect of "Loups Garou" or people who can change into actual wolves at will regardless of full moons or whatever. An excellent film IMO with stunning special effects and rich character development.
Takes place in Romania too which adds some old world flavour. 
You aren't thinking of Jericho are you? Personally I find that series to be little more than a reinforcer of the present "terrorists" are out to destroy our country fear frenzy that Washington wants to maintain over the US populace.
No, it's not Jericho, although I really like that one. On the dvd cover, the series I'm thinking about has two guys walking on a road, one of them is African American with dreadlocks, I think, and he's carrying some kind of stick. Well, that's just from vague memory. 
If I remember correctly, it's based on some comic series too.. but again, I'm not sure.
E.
hmm don't know that one but Id be intrigued if you find a title or even a year for that film.
For post-Apocalyptic, you might draw inspiration from the recent film Children of Men. Imagine a Mythic Europe correspondence in which everyone has become infertile for decades. Good seeds there for fertility magic, Accusations by the Church/Order of the influence of infernal magic, etc.
hmm, I usually draw inspiration from medieval real-life. The series from terry jones (yes, the one from monty python) prove good inspiration as well as books from jaques le goff. In addition, other SGs from my group draw inspiration from the bible. But i have a hard time motivation myself in reading that book.
Depends what part you read. The historical books of the OT can be quite bloody and epic in scope.
And now things get weird.
I use a mix of classic literature (Shakespeare, Arthurian Legend), vintage fantasy (specifically, C. Stasheff's Warlock series, but many, many others, including Tolkien), Anime (Slayers, Record of Lodoss Wars, et alia), video games (Halo 1-3, La Pucelle, Disgaea 1-2, et alia), comics (web and print, manga and american) ... and Opera (Wagner's Gotterdamerung).
In essence, I borrow from whatever I think is neat, and I can make work, and can reasonably fit within the setting. Sure there may be some twisting, for the setting's sake... But it's all about fun, right?
I definitely want the world to be more mythic, rather than Ars Magica-gate.
Thats worthy of applause Kryslin! 