Do a search on DVD-Audio here. It is hi fidelity music on a DVD disc while SACD is hi fidelity music on an SACD disc. THey both sound incredible. The main difference between SACD and DVD-Audio is that DVD-A can have extra features along with the album. SACD does not have extra features, but most titles have the CD layer included, which is nice for playing SACDs in the car.

But since your player plays both, you do not really have to care about the two formats, you just need to find titles that you will enjoy.