There is not a tiny posibility of doing a profesional audio work under OSX yet.
Now, there is a vast amount of software and hardware to do that under OS9.
Apple has left audio development behind, just to imagine that for Apple is more important to produce a toy (iPod) than support profesional audio production companies or to develop a serious audio imput/output ports in place of those same mini plugs that have been used for the last 20 years! with the worst harmonic distortion in the market.
For get about Apple supporting independent audio out put ports for the next year.
I wonder if they'll rebadge one of the Emagic interfaces under the apple name and call it 'iListen' or 'iRecord' or some other 'iCan'tThinkOfACatchyName' type product.
Apple could make any number of changes to the mac's audio capabilities, right now an Atari Falcon is still better than the Mac for connectivity and the quality of the built in audio hardware.
If it wasn't for people like digidesign, RME, MOTU and Korg we'd all be stuck. Even their hardware is a bit overkill if all someone wants is simply better quality audio on their mac.
Still, I'm happy with my digidesign stuff, I couldn't careless if apple remove all audio capabilities, add a 3rd firewire port and sell an Add-on for people to use, I've got all I need for now. At least on G4s you can leave off the internal modem and fit a serial port in it's place so you can get a serial port midi interface for better midi timing.