Since I don't have an all-region player, I have little interest in non-U.S. releases. But if you are into film classics, the British Film Institute has a series of releases that are well-regarded, most of which are only playable in region 2.
They have both British films and TV shows as well as international films. Even when the international films are available in other editions here, the BFI releases often have different transfers and unique extras.
One that looks especially interesting is Ken Russell's THE DEVILS, a two-disc set, full of extras. Even just the film itself is still unreleased on DVD in the U.S.
