SACDs:
Dredg, El Cielo -- the stereo mix is outstanding, don't know about the surround mix (but then again, I'm a two channel headphones guy). Hard rock, along the lines of A Perfect Circle.

Mike Oldfield's Tubular Bells is excellent, as well. Again, as with all of these, am more familiar with the stereo mix than I am with the surround.

Holst - The Planets/Britten - 4 Sea Interludes by Bernstein/NYPO is easily the best sounding SACD I own, so far.

Try to get some Piazzolla, not the orchestral works, but something with Bandoneon. SACD was made for bandoneon and violin.

DVD-As:
Queen, A Night at the Opera -- even has a DTS-24/96 mix, if you have it. The PCM stereo 24/96 is available even if you didn't have a DVD-A player, which is nice.

Koyaanisqatsi

Blue Man Group's Audio is completely silly in the surround mix (drums everywhere -- OMG, you're in the center of the drum section, which is like 90% of the band), but on those few occasions where that's what you want -- they will feed your goat.