Mouse and keyboard. Controllers just aren't very good for either shooters or menus. They're not as useful for the type of games I want to play.
Plus, mods, indie games, it's nice to play on an independent platform.
That said, it's a pain being shackled to a desk. I could use a laptop, but the advantages of using a mouse always come with the inconvenience of having to find somewhere to put a mouse.
Oh, also, it's cheaper. I spent £500 on a PC two years ago and it still runs everything. That's either more or less than a console depending on the point in the console's life cycle, but since PC games appear unique in their capacity to both be good and cost less than £40 on release I'm happy to say I spend less. Or realistically, I spend as much as I would on a console, but I get more games from it. And it's my opinion that those games are better. Consoles are opening up to less restrictive distribution methods, but PC is the platform with the easiest route to releasing something fresh.
Oh yeah, and I realise that given the topics of things that have been written and talked about in the magazine in the last week I sound like a bandwagon-jumper, but I'm often put off by the marketing. These people do not want me as a target audience.