I'll second "Band of Brothers". Excellent mini-series and also a great book. The book won't quite sound as good as the mini-series on your HT, though.
Have you checked out "Gladiator" yet? The opening 15 minute battle sequence will give a through test to any Home Theater setup. The rest of the movie is quite good (IMHO, of course), with good sound mastering and picture throughout. I *think* it's DTS-ES too, but I could be wrong.
The 1994 hit "Twister" is also not a bad movie, but has some amazing sound, esp in the tornado sequences. This one will test any subwoofer to its limits! Also the surround effects are pretty decent as well. Best of all, you can probably find this one in the bargain bin for $10 since it's almost 10 years old. Standard DD 5.1, but it is THX mastered.
Another personal favorite would be "Ronin", from a few years back. Many intense car-chase scenes that make full use of the surrond channels, and an excellent plot to boot.
For a newer movie, "Finding Nemo" is also pretty cute and has some startling HT effects. In several "gimmie-somethin-to-test-my-new-sub" threads on other forums this one is getting high ratings. Several scenes have very strong *subsonic* effects that can only be fully appreciated with a good subwoofer (so I've been told). Surround effects are great and the story is cute, if not actually pretty decent.