Even though Rockstar's Grand Theft Auto V has been released three times over the last year and a half, there doesn't seem to be any decline in demand for the game. On the contrary, the launch of the many times postponed PC version is officially a success with 1 million copies sold during the first 24 hours.
It's SteamSpy who reports this on their official Twitter account, where they also note that the number does not include copies bought or played outside of Steam. That probably means that the game has sold even more over the first day on the shelves.