Gladiator (sound, contrast and detail)
2001 (the interstellar tunnel and the music)
The Big Sleep (Bogart - contrast)
Casablanca (contrast, cinematography)
Sound of Music (the start scenes, lot of Technicolour and high-frequency visuals)
Tron (well, I just thought I'd stick that in
Alien (sound, high-frequency visuals, superb opening, bass response)
Episodes of Space:1999 (just re-issued in re-master with surround sound)
Blade Runner (visuals, contrast, music)
Le Mans (colour, detail)
The Battle of Britain (flying scenes)
Star Wars (the opening scene, the first dive into the DeathStar trench)
Cyrano de Bergerac (Depardieu version - incredible cinematography, especially the sword fights)
The Duellists (similar reasons, but with superb lighting and atmosphere)
The New Captain Scarlet series (a real test - superb widescreen with 5.1 surround)
Altered States (cinematography and visuals)