Final cut is the best reason to use a mac. It is the best video editing software out there. And then it bundels all well with shake and logic pro. Its basically drag and drop yet you can customize everything at the same time.
Also, Maya is one of the bast 3d modeling software out there. You can use it on a pc but the interface is much better on a mac. Just the way the windows are laied out and everything is better.
Finally, osx has so many built in features such as core animation, core audio, core video, core image, core data, Bonjour, darwin, Quartz, openGL, and smart folder. On windows many of these features come as seperate programs or just dont exist at all. Because of this, it reduces work time on projects as you only have to work on your project and not fight with the OS. These tools also make many things much faster. Like in core animation you just define a start and an end goal or the project. This vastly reduces codeing work as well as the size of a program.