Notoriously better at image and video processing. While PC's have caught up and, in some cases, surpassed Macs, Macs have history on their side and the fact that you can do all this "out of the box" whereas you need to upgrade your PC after market to do it well.
Ready to go out of the box. Needs very little, if any, after market upgrading.
Less likely to be attacked by viruses. It's not as though they're more immune, per se, they just have less chance of being targetted because of the lower usership.
You can pretty much guarantee that anything that says it works with your Mac is going to. Since there is only one maker of Macs, there is only one system to which hardware and software must adhere.
MUCH prettier.
PC Pros:
Much cheaper.
Easier to support.
Can be bought anywhere.
Software is easy to obtain.
While some argue it's easier to upgrade the hardware, Macs have become just as easy anymore.
Better for gaming.
Notoriously easier for networking. Has become better for Macs as major Windows based network systems are becoming more friendly.
I am a former PC user. Check that, I'm a former PC ownder. I still do use a PC at work and have no qualms about recommending them based on the purpose. But I far prefer Macs. I find them to be much more user friendly and straight forward. And it's so much fun to get into debates with people about the merits of Macs vs PCs. Usually, the fun is derived from the fact that most PC users are arguing from ignorance as 90% of them have never so much as laid a finger on a Mac. They may have read about them and their "problems" but most are reading from pro-PC sites. Mac users are arguing from both perspectives because most of us are former PC devotees. The number is dwindling as Macs integrate themselves into more households and the user base is getting younger and younger (to the point where many may really never have used a PC); but for the most part, this is the case.