Funny how your perspective changes. Before I get my HT system, when I would buy DVDs, and I would see a DD or DTS version it was all the same. Now, it is something to pay attention to.

Some of these aren't reference audio but usually still have some good stuff surround/LFE activity nonetheless.

Alien: CE
Aliens: CE
Superman: The movie
T2: extreme or ultimate edition
T3
any Pixar film
The Iron Giant: SE
X2
The Usual Suspects: SE
Braveheart
Jurrasic Park: DTS
Jurassic Park III
Twister
Jaws 30th anniversary edition
Men In Black
Spiderman 2
Indiana Jones trilogy
Close Encounters of the Third Kind: CE