In case you didn't know, GTA IV has been sitting happily on store shelves for a solid five years now. FIVE! Keep in mind that this data comes from the UK only, as worldwide sales are a different can of worms entirely. That said, Grand Theft Auto V is already the region's 12th greatest selling-game of all time, which is certainly nothing to scoff at.
Just imagine how many more sales Rockstar might make if/when the game comes to PC and next-gen consoles! I'm sure many of you are itching to play the game on higher spec machines.