You already listed it, but I just want to note that one of my players is specifically inspired by Game of Thrones. She came to me asking if there was any House of the Order which kept wolves as pets. I showed her the magical wolves of House Tremere and she was off and running.
Cadfael (already mentioned, but worth mentioning again)
Robin of Sherwood (as above)
Dragonslayer
Mists of Avalon
Black Death
Season of the Witch (ok, it's not good but it's entertaining and would make a great ArsM adventure)
1957: The seventh seal (imdb.com/title/tt0050976/) is the movie that introduced the "Knight plays chess with Death" stereotype. Dark and introspective, but very powerful.
I'm surprised no one mentioned the Princess Bride (imdb.com/title/tt0093779/). "Hello. My name is Inigo Montoya. You killed my father. Prepare to die." A cult movie.
To add, check out The Advocate, AKA The Hour of the Pig. imdb.com/title/tt0107146/
It is a movie which screams Ars Magica. The characters seem to step out of a companion story. You have a Paris trained lawyer, a gypsy outcast, a witty law clerk, Lords and Church, even the infernal takes a bow. Very very good. You can twist any of the characters or plots to make a great Ars story.
Also Ironclad, imdb.com/title/tt1233301/
Again almost exclusively a companion sourced movie, but it has a heavy historical flavor, possibly they tipped the salt pot a bit too far, but still fun and interesting to watch how the Lords struggle against King John trying to hold him to the Magna Carta/
I love watching Agora, imdb.com/title/tt1186830/
While this one is outside of the typical Ars setting, the story allows you to basically step into a Theban story and grok the culture of the Mediterranean Sea as well as classis Aristotolean physics.
Oddly I am also tossing out Erik the Viking, imdb.com/title/tt0097289/
Which more often than not is how so very many Ars games seem to turn out.
Dragonheart and Labyrinth are 2 staple books of the fantasy genre as well. Dragons and fae. David Bowie acting as a dark shide lord in his regio is hard to surpass.
+1 to L'armata Brancaleone (epic!) and Season of the Witch. I didn't expect anything of the latter and enjoyed it very much. Witches, demons, repented crusaders, knight wannabes, rogues, doubtful priests... There's a nice story seed for Ars there!
What about Beowulf? I liked the part with the regio and Grendel's mother... (And not only because of Angelina Jolie's 3D version).
Someone mentioned Fritz Lang's version of the The Nibelung, but there is also a nice (if somewhat cheesy) version from the sixties, imdb.com/title/tt0060750/
And then there's almost anything by Ray Harryhausen... Now that The Cradle & The Crescent is out, his Sinbad movies could be easily adapted!
Wow, lots of good stuff here that I had completely forgotten. Also, much of the stuff our Troupe already uses. So i guess there's a good chance I'll find inspiration on all those movies posted here, that I haven't seen yet.
I've found lot's of inspiration in non-fantasy stuff as well, having recently made an ivestigation-style story as a beta storyguide, using the same base setup as in Stieg Larssons "Mænd der hader kvinder" (or The Girl With the Dragon Tatoo). It's not an all that original idea, but a closed off/remote place for investigation with a limited amount of suspects, that you can then flesh out works wonders. Throw in a few surprises and you'll make them feel like they are on Shutter Island
For a one-shot-story (like a Con, or a single session adventure) I was greatly inspired by the movie 'Nine'. Put together a group of individuals that don't really know their true purpose and or what their meager powers could be used for - and let the story unfold. In time they realize that they have different task to fullfil and play very distinct and important roles in the seemingly impromtou party. In the end, it turns out that there was a master plan all along, maybe an architect or maybe just fate. This kind of ending, shares some similarities with the works of M. Knight. Shyamalan, especially the (not so good) movie Signs.
Also, one shouldn't underestimate fantasy when used alongside non-fiction, nor when used to tell childrens stories. Much inspiration can be found in Pan's Labyrinth, for example, if you're into tension, darkness and horror. On a lighter note, I'm also currently working on incorporating elements from the great 'children's movie' The Chronicles of Spiderwich. It has lots of humour and some very good takes on classic tales. The way the work with wards (salt in the windows), dogmas and rules (don't go 'there'), as well as how to appease creatures (e.g. with honey on crackers) is great stuff. Some of the same elements can again be found in a darker version in The Village; again by Shyamalan.
Again, the Game of Thrones books are obviously amazing, but now that the series have started we cannot steal ideas 1-to-1 like we did, when only a few of us had read the books By the way, we have had a lot of fun using Hearttrees in out Scottish Campaign, were we needed some quirk for the Warped Grogs in a Winter Covenant.
Oddly enough, I find the Harry Potter books to be excellent sources of inspiration also. Sure, they're a little campy but the approach to magic is very similar in that it's an academic discipline with specialties. Also, the magical combat scenes in Order of the Phoenix and latter movies are, hands down, the most amazing magical duels ever placed on the screen.
All of the previous ones are either already on my list or just added.
I can't believe no one has mentioned "Flesh+Blood"... a pretty gritty and ruthless depiction of mercenaries during the Hundred Years War. Also, the "Last Valley" is a good one.
Kingdom of Heaven is also an excellent medieval film in some respects. The politics and scenery is very inspirational even if it is a bit more blockbuster-esque.
I have a Tremere in my saga only because of the wolves. She has a Weakness to Animals in pain.
So, in her prelude session, as an apprentice, she rescued a wolf pup. She was late getting back to her parens.
He healed the pup, then Perdo Animaled it into a skeleton.
Years later, she almost bested him in certamen, and resurrected the wolf which he had kept the bones of.
The player ALWAYS has a wolf connection, be it in a supers game, a Changeling games, etc.
AS FOR INSPIRATIONS...
I heartily second Kingdom of Heaven, and in particular the extended director's cut which adds in a lot of stuff that makes the movie as a whole make much more sense. A fair amount of historical stuff, to boot.
ALSO, for a group struggling to see the point of playing grogs or covenfolk, etc. I'm realizing the recent buzz on Downton Abbey can be a source of inspiration for drama, plots, etc. in the class structure of a covenant. If a group likes to focus on personal drama over DEO and Monsters of the Week, Downton Abbey may have much to offer.
All olds films of Wuxia and kung fu from Hong Kong, to me the problems between the Masters, the apprentices and the rivals and enemies are very near to the struggles of magi. Adding that the Iniciation Process are similar to the Martial Training (first Jackie Chan films, and some Samo Hung's oldies).
And i edit to addother oriental film:
My Neighbour Totoro - The basic Faerie friend or Magical friend, or the Monster/Guardian for one Covenant.
To me, Name of the Rose is the best example of a late Summer Covenant quickly and precipitously going into Winter. Literally all typical Ars covenant conventions are represented.