Just to add one thing to what Chris said about SACD & DVD-A, both formats may be niche, but if you listen to a lot of Classical and/or Jazz, SACD has a very larger presence in those areas as one can see by checking out this website: SA-CD.net. In order to listen to SACD (or DVD-A) on the Oppo, you will need to either use the multichannel analogue ouptuts (assuming you want to listen to the multichannel mixes, otherwise stereo would be fine, unless you come across that rare release that doesn't have a stereo mix) or you would need to use the HDMI output and stream SACD as DSD and convert it in your AVR or convert it in the player and send it as PCM over HDMI to your AVR, if you have an AVR that can handle mutlichannel PCM or DSD. Just remember that if you do decide to listen to SACDs on the Oppo using the Oppo's internal converters that it downconverts DSD to 88.2kHz/24-bit PCM, so you will not be listening to SACD at its best possible resolution, which is a pure DSD 2.8224 MHz 1-bit data stream. In contrast, the PS3 converts SACDs to 176.4kHz/24-bit PCM which many believe is a much closer aproximation of the capabilities of DSD, but still hardly ideal.
Have fun with your new player!
Brandon A. DuHamel
Big Picture Big Sound Writer/Blu-ray Reporter
Blu-ray & DVD Forum Moderator
'"In a strange game
I saw myself as you knew me
When the change came,
And you had a
Chance to see through me
Though the other side is just the same
You can tell my dream is real
Because I love you, can you see me now."
- "On the Way Home," Neil Young