Grand Theft Auto V has sold over 30 million copies, proving that the series is a juggernaut. Despite it's popular online mode, it's probably fair to say that the single player experience is what made the series what it is, which goes to prove that despite the many popular multiplayer games out there, single player games still have plenty of appeal.
There is certainly plenty of proof out there that single player is very popular, Skyrim sold over 20 million copies and the Assassin's Creed series, which itself is a multi-million selling franchise, is definitely more popular for its single player experience. Nintendo also provide plenty of excellent single player experiences. So even though the hype generally surrounds multiplayer games, it's nice to know that there is still love out there for the single player.
But what about you? Where do your loyalties lie? Do you still feel that single player is relevant, or is it all about multiplayer?