08-20-2006, 03:53 AM
Most people who use Mac's for pro audio don't use the built in sound card. Mostly because they need multiple channels in at a time. You mentioned you would use an M-Audio device with a PC, well you can use them with mac's as well.
As for hard drive space, Apple offers an XServe Raid with will give you up to 7TB of storage for a total of 9TB with the 2TB you can put in the Mac Pro. It would connect using 2GB fiber channel. There will probably soon be some after market solutions to putting more drives inside the Mac Pro itself just like there are for the G5 Powermac. The computer itself can accept as many drives as you want as long as you can fit them in the case, just like any PC.
If you go with external solutions for storage and sound, they wouldn't be using the Mac Pro's power supply so you wouldn't need to worry about it being to low.
As for video cards, I think you are stuck with what Apple has to offer. Last time I checked, the video cards for mac's were built for mac's, as in different then the ones built for pcs, however I could be wrong. But the ones built for apple at least have the special apple video connector for their displays so that's at least one difference still.
Also, you can't just compare Mac specs to Windows specs. I have an 800MHz G4 Powerbook that easily out performs my friends 1.5GHz Dell.