The honest answer to your question is this: I was only 13 when Titanic came out. The hype before, during, after, and around Titanic was incredible. I had never seen a movie be so incredibly BIG while it was STILL IN THEATERS, before, and I haven't seen any movie be that big since. I feel like, when that movie was new, the enormity of the public reaction to it made it into more than a cinematic event. It made it into a cultural event, and eventually into a historic event, as it is the current number one grossing film ever. I think before it, it was either Jurassic Park or the first original Star Wars. I wasn't born for Star Wars and I wasn't old enough to really understand Jurassic Park when it was new. But I saw Titanic in theaters. So, I feel like I was part of something big because I saw the movie in a theater right when all the hype and buzz was happening. I want to be able to tell my kids(when I have them in the future, sure as hell don't have any now) that I was there for it. I won't be able to say that if King Kong surpasses Titanic because I have no plans to see it in theaters. It just doesn't interest me that much. And honestly, the hype surrounding King Kong is NOTHING compared to what happened when Titanic came out. It just isn't even close. You couldn't watch TV, listen to the radio, go to the mall, whatever, without seeing or hearing something about Titanic. Even without the hype, I just don't think a gazillion dollar remake of a film about a giant ape could be deserving of a spot in history next to such cinematic landmarks as Star Wars and Jurassic Park. I think Titanic is more deserving of it than King Kong.
And 'My Heart Will Go On' isn't really that bad.