I attended WWDC and took many notes on the audio sessions. If anyone would like a copy of my notes, please e-mail me.
Where we are NOW (OS 9):
16 bit, Stereo, 44.1KHz, constant and variable bit-rate formats, growing use of native processing, loose synchronization model.
What's coming in OS X:
24-bit (integer), 32-bit (floating point), 5.1, 11.2 and bigger surround sound modes, 96KHz and higher sampling, more complex encoding, more native processing, hardware acceleration, tight synchronization (over network and with SMPTE).
Audio/MIDI is DRASTICALLY changed from OS 9, but it's going to be worth it. The guys that wrote OMS (Opcode/Open Music System and Studio Vision Pro) are now working to build the OS X audio subsystem which will include superior audio and MIDI support (built in, OS level sequencing, synchronization and software synthesis too - using G4 Velocity Engine!!!).