Your Preference...
First, let me start off by saying that I am a BIG Mac fan, and I'm also a Computer Science major. I've got a lot of experience with both platforms in almost every aspect, including music production.
As far as audio production goes, it really comes down to platform preference. In the past, especially when Digidesign was developing ProTools specifically for the Mac, Macs definitely had the edge. When companies started developing cross-platform, PC's became viable for production, as well.
Nowadays, pretty much every type program is available for both Mac and PC. Furthermore, with the advent of non-legacy technologies like USB and Firewire, almost all new hardware is also cross-platform. Which means that if you like Macs, there's no reason to go PC. If you like PC's, likewise.
Personally, I like the Mac's file system much better than PC's. With the experiences that I've had with large audio projects (64+ channels of audio), I've had a much easier time managing all those files on the Mac. Not that Windows is bad, but the Mac's drag-and-drop capabilities are a little more polished and intuitive. Also, it's been my experience that audio hardware is a bit easier to set up on a Mac, but that probably doesn't matter if you know your stuff.
Cubase 5 on my Mac ROCKS! I've got it hooked up with
a Tascam US-428 board, and it works great. The driver install was a snap, and I had the board and Cubase up and running together in about 10 minutes, no problem.
Like I said before, it really comes down to platform preference. If you don't have a preference, find some friends with Macs and PC's and play around with them. Get some experience, have your friends show you the platform strengths and weaknesses, so you can make an educated decision. I wouldn't worry about which is "better" for audio... they both will give you good results.
Rick