As for the Mac vs. PC debate...
I'm sort of going through this myself right now. My laptop - which is my only computer - is about three years old now. Which means it was already obsolete by the time I walked out of the store with it.
I've worked on Macs from time to time, and I don't thinking making a total switch would be too hard for me at least. Most basic programs - well, at least files - are more or less portable between platforms, especially when it comes to media files (music, MIDI, pictures, movies, etc.) Microsoft does make Word for Apple, and it's more or less fully compatible. *One sort of short cut when dealing with text documents is just to e-mail the text to yourself, from one platform to the other - and then just reformat as necessary.
Yes, Macs are more expensive, but they automatically come bundled with more of the essentials, rather than just the OS. There may be less software available for the Mac, but it's more a case of there being less of the same types of programs available for the Mac - i.e. word processing (Word Perfect, Word, Works, etc.) Mac started off as being "specialized" and proprietary, and they've stayed that way.
BK - If you do plan to start getting into some more serious music and video editing on your own, then a Mac would be the way to go. -Of course, you'd have to buy and learn some of those programs.

As for iTunes - It's available for Windows now, and Mac makes PC-compatible iPods now too.
As for your peripherals - printers, scanners, etc. - not all of them are cross-platform capable. However, at least with printers, they're all pretty reasonably priced now, so buying a new one is not too much of a financial pinch. *And Apple has a bunch of "get a free printer" offers when you buy a Mac.
As DR Panni mentioned, the Apple stores have workshops scheduled regularly. Additionally, if you are seriously considering making the switch, just go into an Apple store and sit down with one of the employees - I think you could even consult the people at the "Genius Bar". They'd be more than happy to answer your questions - and eventually sell you a system too! Apple's follow up service is also pretty good - sometimes they'll even "extend" the warranty just to keep the customer happy should something happen with your computer.
*My friend, Chris, who did the "Coming Attractions" trailer is a Mac person - he's been trying to get me to switch for years. You could always consult with him - he likes spreading the "gospel of Mac".

-However, I do have to note, that he does keep a PC in his studio setup since one of the sampling programs he uses is only PC-based.

**Chris also has a habit of coming across special sales and closeouts on Macs, some pretty astounding deals.
I'm planning on purchasing a new computer towards the end of January. It will, to be honest, depend on my "discretionary funds" I have at the time. But a Mac is seriously under consideration.