Ok, Scorch, I will try my best to explain what the advantages are for owning a Mac.
A few things about me, though (so that you can see where I was/am coming from). I've owned a mac for a few years now, was a huge (and still am) a hardcore gamer (both pc and consoles. So gaming a big deal for me), used windows for all my life, know a great deal of windows (thus not familiar with Mac OS).
So, here's what I have seen by owning a mac:
-Security: a great deal of security from the start, with the occasional update. I know that windows does have good security (but only after you install a few programs. Mac does this out of the box).
-Programs: I'm talking about out of the box here, not what you can buy for it. iMovie, Photo Booth, etc. are great programs compared to Windows PC counterparts. Also, there is really no bad programs that would be installed (meaning useless, as Windows does install a good amount of useless crap when you buy the program, ie trials and stuff). Also, it seems like Adobe software is MADE for Macs, works wonders on my Mac. If you are into photography, design, graphics, art, etc. Macs have a ton of software that makes it great.
-Nice, clean UI: the taskbar is nice and small, can drag and drop (while I'm on that subject, Macs have the ability to drag and drop nearly anything, from putting files into folders to putting files from your desktop into a program. Yes, Windows does do this, but not for programs since they usually require you to "browse" for the file, on Macs, you don't browse, you can simply drag and drop into the box. Not a big deal, but a really nice feature). Small animations on the taskbar, little arrows that show you what's open. Also, a cool feature is the ability to set your corners of you Mac to shortcuts. On my macbook pro, I set the bottom left for "show all open windows" while I set the bottom right for "show desktop." You can set all four corners to whatever you like (well, pretty much). You can also set your Mac to have up to 16 (yes, 16!) desktops, meaning, you can have one desktop for your mail, then have the desktop to the right have your Safari browser, while the one to the left is for your AIM/iChat. You can set programs to open in spacific desktops (IIRC, they are called spaces). Really helps orgranize your programs, and keep your desktop nice and tidy.
-iChat: it's like AIM but a lot better, you can see (because of the icons), who you can call chat (via a microphone), video chat, or just text chat. It's really nice and a lot better than AIM, imo.
-Time Machine: Oh man, how I love this, it's so insane how much this little software can do. I know Windows can do this (with programs, or the built in program) but not as good as time machine. What this does is allows any external harddrive (must be external) to backup your files (either entire hard drive, or only certain folders/files) to the hard drive. You can set a specific time for time machine to back up the files/folders, or you can manually do it yourself. If, for whatever reason, you are missing something, you can restore your files/folders to it's previous state. You can restore certain files/folders or all the files/folders from a specific date.
Bootcamp: Pretty much amazing, yet so simple. A free (last time I checked) program that allows you to partition your hard drive into 2 seperate partitions and load windows on one side and your Mac OS on the other side. You can do this at anytime, because I believe it will still keep everything on your mac OS and just delete the amount of space that you have (say you have a 160GB hard drive, and you want 100 GB for Mac OS while 60GB for Windows, all bootcamp will do is make it so you now only have 100GB of free space, instead of 160GB of free space). So, now you can load anything you want, whether it be Windows Only programs or Mac OS only programs. It your choice. The only thing you technically need to buy for this is Windows.
Right now that all I can think of (mainly because I am working on a project due for class that requires Windows, so I am not on my Mac OS). Sure, it's expensive from the start, but it's worth every penny, in my eyes. My Macbook Pro (17" 1920x1200 glossy screen fyi) is outdated, but man, it runs as smooth as it did 2 years ago, and even has the battery life to prove (lasts atleast 4 hours with minimal settings, max settings tend to be about 2.5 hours). Let me tell you, it's definately a show off item (well, unless you go to a technical school, like I do, in which nearly everyone has a macbook or a macbook pro). Plus, the shelf life of macs (from what I hear) tend to last almost double what the windows counterparts lasts.
Granted, the hardware aspect will never be at the level of Windows machines, but it does have good enough hardware for basic needs (including gaming). Just don't expect to play crisis on max settings on any mac (it nearly crashed my macbook pro when it was released, and at the time I had the best macbook pro you could get).
On a side note, their tech support is TOP NOTCH. No joke, I love them so much, so kind and friendly. If you are in a real hurry then most apple stores can diagnose your problem on the spot.
I hope I gave you good advice, without being biased.
*If you need any help, comments, questions, etc, feel free to PM me or ask here, and I will try to answer them.