I think both platforms have their usefulness. I do most of my email, Internet browsing, and business stuff (Excel, Word, Quicken) on the Gateway laptop I'm using to write this. My Mac is in the studio connected to the Internet via wireless. I mainly use that Internet connection for downloading application updates. I will occasionally burn a CD on the laptop, but 95% of my audio work is done on the Mac.

If there is a Mac equivalent to the Windows Registry, I've never used it. I don't know any Mac gurus...haven't needed to.

That's different from having questions about the application itself and you do have to watch which version of OS X you have and whether the application you're using works with that version.

For instance, Apple just came out with Leopard (OS 10.5) and hardly any audio apps are qualified for it yet, but updates are in the works. Kind of like Vista in that it's very new. However, Apple has CoreAudio and CoreMidi, so I'm not really concerned about losing audio functionality. Apple knows it's a big selling point for their computers. But those are the things you need to know about: if you were to buy a Mac today and Protools tomorrow, it wouldn't work very well until the applications are updated for Leopard - which WILL happen soon, I'm sure.

However, Garageband comes with all new Macs and you could certainly be using that on day one to make music. Apple's built in audio is not bad, but you'll still want an audio interface for Mics and Guitar input. Many audio interfaces (such as M-Audio) are plug and play with Macs.

I forgot there's an even cheaper route into the Mac world: the Mac Mini. $800 for a 2GhZ Core2 Duo. Get another GB of RAM for $50 and you're pretty much set. It also comes with Garageband. You can use your PC's keyboard, mouse, and monitor with it. It's a little more limited in expansion than the iMac, but certainly serviceable. I would recommend an iMac unless you just can't put it in your budget.