Need Help Deciding What Computer to Buy

Hi guys, i recently sold my computer (a 2011 11 inch Air if you must know) and I am trying to decide what to get. I was previously thinking of buying the new Retina MacBook Pro for its potential gaming capabilities combined with such a svelte and light form factor, but that is now out of my price range. I have recently read several posts on why PC gaming is so great, as well as how to build a cheap but powerful gaming PC. So now an affordable gaming PC has also become an option.

To get to the point, I would appreciate if you guys would help me decide by making an argument for me buying either a

A) 2012 13 inch Air with 256Gb SSD or,

B) An affordable gaming PC.

Potentially important details: My Air almost never left the desk while I had it, I love mostly FPS shooters like Halo, Battlefield, and Crysis, but I also enjoy sims; After using OS X for quite awhile, I hate Windows with a passion as it is shockingly and buggy in the few comparisons I've been able to make, but I could put up with it if was a marvelous gaming PC; and finally, I have quite a bit of important data and such in a Time Capsule of my previous Air (I would need some way to transfer that data onto my new Windows computer if I ended up getting one).

Thanks to anyone who ends up helping!