Also in no particular order;
Fifth Element R1 - Reconstruction sequence & Diva sequence - true classics!
Muppets from Space R1 - chapter 3 Breakfast - A great self contained sequence, great colour and detail & Funny.
Lost In Space R1 - opening sequence, attack on the hyper-gate - great contrast and encoding quality, sound is good, but watch the front left channel on the second explosion, it's taken out more than a few speaker cones and amplifier channels!
Seven R2 - in the Library (Chapter 8 I think)subtle shading of light, detail in the paper and skin tones while backed with wonderful music - the ambience on both surround tracks is wonderful.
Chicken Run R2 - The Pie machine - also as used on DTS demo disk 5 - really uses the discreet rear channel plus excellent video encoding (R2 disk better than the DTS demo disk)
Brassed Off R2 - 'Orange Juice' (chapter 6 I think) - not the best encoding in the world and only 2 channel sound, but viewed at a sensible distance, the skin tones and textures plus the evocative sound track makes a pleasing sequence.
The Corrs - Unplugged R2 - 'Radio'- shot on 16mm film, there is quite a bit of grain but on a properly set up system that also gives it a real film quality. The sound has an unusual mix (the placing of the artists is very spaced out and static, inspite of the camera view point) but still uses all the channels well. (plus, of course, close ups of Andrea!)
There are plenty of other dvds that are exceptional quality (R1 Legend of Bagger Vance, R1 Traffic etc..)but the hardest part is always finding a suitable segment that is interesting, short enough, self contained (for plot) and navigable (i.e. you need to be able to find it!).
Oasis