PC gaming is about a lot more than graphics. Even if you just have a mid range PC that you also use for every day use, games like Skyrim are endlessly better because of the modding community. You also have the unrivaled multi tasking (i currently have FF14 waiting in the background while i type this and am watching Chuck on my other screen), and let's also not forget the mouse and keyboard.
Of course console gaming can one up the PC in some aspects, but that works both ways. Graphics is just a small part of it, and those of us that choose to spend the money on high end rigs do so for the same reason many people spend several thousand on massive TV's and audio systems. We believe the higher end experience is worth the expense.
Being able to edit and render 1080p video at high speeds is also very nice :P
