The average PC has far better graphics capabilities and the keyboard combined with a good mouse are far superior than any console controller.
A Keyboard and Mouse isn't superior to a Console Controller. They are merely different. Sure, I would never want to play and RTS or a FPS on a controller. However, I would hate to play a 2D Platformer or 3rd person game like Arkham Asylum with a keyboard. Just as the best way to play Wing Commander and the like is a joystick. Different tools for different jobs.
What makes a PC great is the support for any type of controller you have and a huge back catalog of games going back 20 years (or more with DOSBox or other emulators).