Well at first glance I was ready to respond with adding up all the years that I have played, but then I saw the online part and that puts my hours down substantially. I am more like @cyclistbabe and I like playing the game offline a lot more usually. I do play online though, but it is probably much less than 50 percent.
Right now, more than 300. And to be honest, I think it should be much more. This game is really addictive and I just like to play it every single time.
Probably around 100 or so hours. I haven't had as much time to really play it as maybe I'd want to, but I always play it when they release major new updates.
Over 500, which sounds like a lot but I'm surprised it's not more. The game never gets boring to me I play for a few hours a night now, sometimes even six hours in a row. I do races, mod out all my cars, do CEO work, heists. This is by far the most fun I've had with the game with all the new DLC's coming out. Well done Rockstar, well done.