Ah, another fellow musician, welcome!
You should check out
Audio Evolution, it looks very promising.
It's a hd-recording app, and the newest version (4) will be optimised for OS4.
I think I heard somewhere that there would be a demo on the OS4 contribution CD or something.
As for hardware, well, it's not looking so great yet.
There's support for the SB Live! and that's pretty much it for now. :-(
And I think it will be a while before we have 24 bit, high samplerates and multi I/O support. As I understand it, the AHI sound system in it's current form simply isn't up to the task.
Hopefully it will be developed further soon.
