Hey 2channel - the older Oppo players were not actually good transports. The digital output on those were really bright/harsh. If you wanted to get into a stand-alone DAC, I would highly suggest a better player. Even a really cheap $100 Sony Bluray player has better digital outputs than the old Oppo. The new Oppo (103/105) have good digital outputs.
You're probably better off getting an Oppo 95 or that Marantz SA 8003. I think the Marantz is going to sound better. Be aware that you're paying for 12 audio circuits on the Oppo 95, where there are only 2 audio circuits on the Marantz SA 8003. The Marantz has fully discrete audio output buffer circuits, where the Oppo uses SMD dual-channel op amps.