I play PC games partly because the PC isn't in the lounge. I've got consoles in the lounge for playing with my kids, but the TV is nearly always in use for watching soaps or game shows or reality rubbish that I can't stand, so I hardly get to use the consoles.
My PC is MY PC. No-one can tell me I can't play a game because they're watching TV, I can go on it whenever I want without disturbing anyone.
That's a big bonus for me, in addition to all the other things I get from PC gaming - mouse and keyboard controls, but with the option of using any other controller if I want, higher resolutions and better quality graphics, cheaper games, exclusives that simply aren't possible on consoles (compared to console exclusives which could easily be done on PC).
Plus building a PC for gaming is fun, and gives you a sense of achievement that you just can't get from consoles.