I don't really have any new ones to add, but for most visually stunning and tonally unique, it's definitely John Boorman's
Excalibur. And it's fun to play spot the famous actor before they were famous. Gabriel Bryne, Liam Neeson, Patrick Stewart, and Ciarán Hinds all had roles here, early in their careers. And while Helen Mirren started her career very visibly in the 1960s and was certainly established in the UK by 1981, she was nowhere near the international star she became decades later.
Paul Verhoeven's
Flesh+Blood is definitely a good, bloody, gritty flick.
Though not as striking as either of those films, I have always loved Dick Lester's
Robin & Marian, which I think contains one of the most realistic one-on-one battles, with the aged Robin of Locksley (Sean Connery) and the Sheriff of Nottingham (Robert Shaw) going at each other in full armor. Aged or not, you definitely get a feel for how incredibly exhausting it would be to actually do battle in such rigs, wielding heavy weapons.
And finally, though you may not groove to the Shakespearian goings on, Orson Welles'
Chimes at Midnight has a marvelously edited sequence recreating The Battle of Agincourt, that Welles shot on a very tight budget with limited resources, but it is really the cinematic blueprint for all such subsequent movie campaigns. It very obviously influenced Gibson's
Braveheart, but you can also see it in
The Lord of the Rings trilogy and beyond.
A piece of it can be seen below...