Not a lot of sword and sorcery, but one of the best medieval movies ever made
Conan the Barbarian - pre-medieval, and not a lot of armor, but plenty of ass-kicking. And a second for Flesh+Blood - it has Rutger Hauer doing what he does best, and Jennifer Jason Leigh doing lots of things in not much clothing.
Hawk the Slayer is perhaps the most perfect movie out there ever. It takes itself completely seriously but is so campy and bad that it is a riot. I can only see how alcohol will improve this already perfect feature. It even has Jack Palance in it though he looks decades older than his father!
One movie to avoid like the plague is the absolutely terrible Druids with Chris Lambert. The fight scenes are an indistiguishable mess and the plot isn’t much better. Do not see this movie. You’ll want revenge on the makers of it… I certianly do.
i liked Black Knight. Martin Lawrence is better when he has people to work off of, but he did pretty well in Black Knight.
Two more nobody’s mentioned:
Tarkovsky’s tremendous **Andrei Rublev** and another Sean Connery vehicle, The Name of the Rose.
And surprisingly, nobody’s mentioned the best Robin Hood, Errol Flynn’s The Adventures of Robin Hood. I suppose any version of Othello or Macbeth counts, too.
How about springing Prince Valiant on everyone…
[sub]OK, I’ll go now[/sub]
I recommend Terry Gilliam’s Jabberwocky. Funny in parts, goodly amount of swordfighting, and it captures the feel of dark ages Europe better than any movie I’ve seen.
I was going to mention Jabberwocky, but you beat me to it. It’s not that good a movie, but it was the first to portray the Middle Ages as being dirty (in the literal term). Prior to that, everything was clean and you got the impression people bathed regularly. Gilliam made it clear they did not.
Going back to a previous era, though, there’s The Court Jester. Completely innaccurate, of course, but very funny.
Fill in the blank: “The pellet with the poison ________________ .” 
Mmmmmmm…Henry V… drools, a la Homer Simpson
Along those lines, I also highly recommend Orson Welles’ Chimes at Midnight, which uses a composite text taken mostly from the Henry IV plays, with some Henry V and just a bit of Richard II. It focuses on the corpulent, cowardly yet supremely entertaining and larger than life Sir John Falstaff, and the breakdown of his relationship with Prince Hal, the future Henry V. It’s got a great cast – Welles plays Falstaff, and Sir John Gielgud is Henry IV – and the portrayal of the battle of Shrewsbury is easily as good as Branagh’s Agincourt (and coming from me this is extremely high praise). Indeed, I think it was an influence, as there are some very similar shots…
The one drawback, though, is that it’s very hard to find. Though it turns up on ebay sometimes – that’s how I got my copy. 
As a side note, which I forgot to post, Chimes is another movie I’m not sure would sit that well at a pizza and beer gathering. OTOH – Falstaff would approve… 
The 13th Warrior?
Lord of the Rings?
Brian
I would go with The Court Jester as a way to appease those who are annoyed at not having The Holy Grail. Just as funny, and not so often repeated. “The pellet with the poison is in the vessel with the pestle, the flagon with the dragon has the brew that is true.”
So, you have your light medieval one picked. Then you pick one for plot (such as Henry V) and one for all out action (say, Conan).
If Monty Python and the Holy Grail is wearing a bit thin, why not substitute Jabberwocky? That way, you’ll still get your Python fix, or near as dammit.
Unless someone or several someones already mentioned it while I wasn’t paying attention, in which case never mind.
Pochacco mentioned The Navigator - I agree. Wonderful & moving. Medieval villagers must put a cross on top of a church steeple in a modern city to save their village from the plague.
There are plenty of movies. Some that I have in my collection are
A Knight’s Tale
Excalibur
The 13th Warrior
Robin Hood Prince of Thieves
Braveheart
Conan
Crouching Tiger, Hidden Dragon
I’d also suggest The Seven Samurai
Highlander (the original is the only one worth watching–stay away from the sequels)
The best selection of medieval films is surely that compiled, with commentary, by medieval historian Paul Halsall as part of his Medieval Sourcebook.
Early on in this thread someone mentioned The Sword and the Sorceror . I second the motion. Not that it would win any awards, but it is highly entertaining and Lee Horsley had quite a body. I suppose Kathleen Beller did too but that’s not the way I lean. As was said, it does have every fantasy movie cliche ever. But I like it at the end, when Alanna turns to Tallon and says" Don’t we have some business to transact?" Oh heck, just watch the movie, it’s fun.