I know a lot of people mention the train crash scene in Super 8, but I find the later scene where the alien corners the kids inside the crashed bus to be much better balanced over all. The train crash is a little hit and miss. Yes, it immediately impresses people because there's a lot of bass, but only about half of the scene seems to have been done properly. There are some amazing thuds that will test your sub's ability to start and stop immediately, and it will also highlight subs that are prone to running out of steam. But, half of the scene (bits and bobs of it) just lacks impact where there should be plenty of it, and some of it is just plain OTT.
Another one mentioned is Tron. Again, it tends to impress because it has a lot of bass (seems to be mixed that way throughout the film). The funny thing is that if you play this film on a system with subs that can control the bass properly, people ask where the bass is, because they're not used to hearing it how it should be.
The Dark Knight is another film that I would say the sound quality is a little overrated, as well as favourites like the Transformers movies.
If you really want to get all of your speakers working over time and the sub into overdrive, Hot Fuzz. Yes, the sub channel is excessive, but it has purposely been mixed that way, which will be understood by those who are familiar with the types of films that it is paying homage to. Some of the action is non stop, with all speakers going at it together, relentlessly. It isn't the best quality sound out there, but I'd say its a bigger assault on the ears than Pacific Rim. On a system that is lacking, it'll sound a mess and probably give you a headache, but if the system is well set up and up to scratch, its a wonderfully busy soundtrack that isn't the slightest bit fatiguing.
I watched The Family tonight, and I have to say that the audio on that film - music, dialogue, and effects - were excellent. The animated feature "9" is a fantastic example of detail and clarity, if quality is called for. As I say, it depends what aspect of a film's audio soundtrack you want to showcase, but based on the thread title, give Hot Fuzz a try.