Regardless of how you feel about Conan, and his hair, this video sums up many editors experiences with FCPX.
Conan O'Brien Editors: Apple Final Cut Pro X Is Easy To Use
HAHAHA that's sooooo funny, thanks!
I'm still on an older version of final cut but I'v been wondering what the uproar about final cut pro x is about, and looking at some of the screen shots in that video, i can see why. It looks like freeking imovie, it's totally different!
For the OP: In your position, I would pick a beast PC, you'll save a lot of money and can upgrade the machine in time. Also, you have a lot more software options for the 3D side of things. For video, yes there's Avid but I used that for 2 years and hated it, very clunky, difficult to learn. They might have updated it by now but there's prob a ton of alternatives on PC.
I personally use Macs, I find the OS a lot easier to use. It thinks like I think, I felt like I was always fighting against Windows. I do a ton of photo editing and a bit of video and I think macs are great for that, but if your doing a ton of professional vid and 3d stuff then I say go PC. Not because you can't do it on a mac but because it's a heap more expensive if you want to and theres not as many software options.