I use both for work doing motion graphics, 3D stuff & video editing, they've both got pros and cons. For the most part, I like OS X over Windows 7 although it's downright regular how it will overwrite an existing folder when copying another folder of the same name to the same location, instead of merging the contents. Final Cut Pro was the don a few years back, but they left that behind to release the useless turd that is Final Cut X, which turned a lot of heads, myself included, back to Premiere which now utterly kicks FCX into a sorry 3rd place.
I've built a few PC's for myself, way, way cheaper than the equivalent iMac - even my current machine, a new dual Xeon badass, comes in a couple of grand cheaper & way more powerful than the current top of the line Mac Pro which they've let rot for the moment. Running OS X on it as a Hackintosh is a bit of a pipe dream, but as far as I know, you've got to have a specific list of motherboards, graphics cards, etc. to get it to work properly. Linux/Ubuntu would be dope, but you can't use After Effects, PS, C4D, etc. on it unfortunately. I have a 2008 Macbook Pro & ipad for fannying about on; the MBP is now way too old and slow for me to do any sort of high-end work on. Cost a fair bit at the time, but it's lasted well and paid for itself many times over. Ultimately, get a PC if you're low on cash and/or like tinkering under the hood, get a Mac if you're rubbish with computers and need them to just work for you.
But yeah, fuck all that Apple fanboy wanker smugness, queuing overnight to buy a phone, then wanking themselves to death over a portrait of Steve Jobs on the cover of Time magazine. Cunts. And the planned obsolescence on Apple's part on everything they produce. Cunts.