I have PC as well, but I usually only play PC exclusive games on it, because I suck at playing games with a keyboard instead of a controller. x'D
I'm exactly the same. Sometimes mods will persuade me too...or Steam sales. I regret attempting to play L.A. Noire on a PC.
It's kinda hilarious watching me and my boyfriend attempt to play it, though.
But you can use a controller on PC
It's the only way to play ports like Dark Souls 
I seriously need to get one of those...I keep putting it off.
I think so, it shouldn't be a problem as long as you run Windows. But it's always best to double check before you buy it, especially if it's from a third party. I bought a Microsoft licensed 360 controller a few weeks back for like $45 and it works like a charm, but I'm sure you can find cheaper ones 
Ooh, didn't realize Microsoft made some as well. That's reassuring.
Sounds like a lot of people will be on PC. I'll just stay over here on my last gen console since I already blew my money on the two nice things I can have for the next few years. DAI and a new TV that actually works.
Well, I might end up playing mine my 360. Still not sure yet. I'm definitely not getting a next gen console just for the sake of one game, though. I still probably have only about 10 games for the 360 and they are largely Bioware games. 