I agree and disagree with lots said already. I use Windows XP (my M-Audio cards do not have Vista drivers, and Vista would take too much RAM for the OS from my 2 Gb RAM setup anyway). My friend has a MAC Pro-Tools setup. As someone said, Mac is a closed system. You pretty much only have one choice (maybe two), it's expensive, but should work without a headache. The PC is an open system...you might slide a sound card into a PCI slot that shares an interrupt with your video card, and you'll end up with crackles and pops in your tracks. You either need to know about your motherboard's shared interrupts when inserting the card, get lucky, or have a friend who knows help you. When installed properly with quality drivers provided by the manufacturer, there will be no headaches there either. Hardware and software in general costs less for the PC, but can be just as excellent or even moreso in some cases. If you don't browse seedy web sites and are smart with e-mail attachments, you will not get a virus. And you shouldn't run antivirus when doing audio work. That's mostly why people say a dedicated machine is better. You shouldn't use a Windows PC bought with the OS slammed by manufacturer either (i.e. Dell, Gateway etc) as they usually add all sorts of auto-startup programs. Windows should be installed from scratch, unless you know how to disable and uninstall all of the auto-startup programs from a manufacturer. Good luck, there's lots of info out there, but most of it is nestled between flame wars.