So, what to your knowledge, does OS X excel in? What does it do well that makes it better than other OS's; according to you, when it does them?
Would Graphics work and Animation fit in that area or should I just stick to Windows? I mean I can always install Windows on the Mac for the few times I may need it.
I can't give a definitive list, I will only cite examples where I have some personal experience.
1) What are the people around you using. In the community I live it would not surprise me to find out that the majority of people are Mac users, certainly in the circles I'm in the usage is well over 50%. When a friend asks me whether to get a PC or Mac, I ask them what their friends (typically first line of support and help) use. In my circles, that means Macs. There are about 3 or 4 of us Mac users who are informally supporting a dozen or so new Mac users. They went with Macs because the people who would be supporting them use Macs. Incidentally, we are all photographers and so there are some specific apps and workflows that we are helping our friends with.
2) Using images and other written material across a multitude of applications. I'm a photographer, and I (sometimes) run a Gallery. I also sit on several official and unofficial arts Boards and committees. I do my own publicity, plus I help out with the Boards and committees publications. Being able to drag-n-drop images, logos, text clips, etc etc from one use to another ensures I keep a harmonized look and feel across press-releases, web-sites, artist statements and bios, business cards, gallery cards (those little cards that go on the wall below hanging art), brochures, rack cards, newspaper ads, magazine ads, post-cards, emails, etc etc. It can take me a week or so to put together the material I need for a big publicity campaign - but once the material is put together, it takes an afternoon to create all the different packaging (except for the website because of its complexity). Smart folders are critical for me to keep things organized.
For just general photo editing, photo work-flow, and office work I have to assume that Macs and PCs are just about the same (some advantages and disadvantages to each).
3) My wife is the exact opposite. She is concerned with words and research. She is the senior policy analyst for an NGO. She researches online, runs and crunches stats, writes and comments on policy, and reads and sends email with attachments. A lot of emails. She has no interest in how it works, she just wants it to work. She is the only person in her office using a Mac as a work machine.
She doesn't worry about why the projector she plugs into displays her presentation. It just does. She doesn't care how the Wifi connection works, she just likes that the only troubleshooting she has had to do is to turn Airport off and then back on again. The only thing that doesn't work as easily as her PC carrying colleagues is the proprietary VPN solution her NGO uses to connect to the HQ servers, so she fires up a virtualized Windows session to use the VPN. There is a Java VPN client apparently, but its more trouble for her to bug her IT person about it than to use the virtualized Windows. And, the IT person initially thought my wife's virtualized VPN connection would be an issue, but has now admitted that my wife's connection is the only one he hasn't had a support call on. Except when they change the connection protocols and forget to send them to my wife

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My wife wants her computer to work like the refrigerator. She opens it, she does something useful, she closes it. She doesn't care why it works - it just does, and she doesn't have to spend much time making it work.
Incidentally, even Macs have a lot further to go to reach the 'appliance' stage, but I think that is Apple's intent. Why shouldn't computers be as easy to use a stove? (And yes, I know that capabilities and complexities are different, but its a worthy goal to aim at.)
There are issues as well with Macs. I'm not blind to them, and have recommended some people stick with their PCs if I thought that was the best solution for them.
Does that help?