Pretty bummed to hear this on the radio out driving around with the roof off the car today. I could see other people on the news in traffic saying "holy #@#@#" at the same time I was, a pretty surreal experience really.
True Romance was one of my favorite movies in my youth, and I still watch it at least every year. James's character in that film was so incredible it is no wonder he reached the heights he did. If anyone has the time or interest, look up the "Actor's Studio" on uTube, and watch Gandolfini's interview there. It's worth your time if you're a fan in the slightest, and I found myself thinking about some of the things he said about life, and specifically his life, in the last hour or so.
If you don't follow pop culture like my wife does, you may not know that HBO had green lit a new series with Gandolfini being the star, a 7 episode deal called "Criminal Justice" about him playing a screwed up lawyer, for later next year. Apparently David Chase was working on a Sopranos movie for 2015 as well. It's very sad that none of that will ever come to pass now, as at 51 one of the greatest actors of my generation can only be remembered for past work now.
I would add as an edit, commentary on how our society works today, that Gandolfini's wikipedia page had him updated as dead by the time I got home, less than an hour after the announcement.