Bungie has released the launch trailer for Destiny: The Taken King and you should watch it. It's right there at the top of the story. I'll wait.
The Taken King seems to really improve the design of Destiny in multiple ways, and those systems will be coming to everyone who owns the game, even if they've never purchased an expansion or The Taken King. The new strikes, in particular, seem like they're going to be much more enjoyable. We'll have plenty of coverage once the content launches to test it all out.
We're on board so far! The launch trailer, on the other hand ... does that song really go with these visuals? What am I learning here outside of the fact that Destiny's visuals would probably look really good airbrushed on the side of an 80s-style van? It's such a strange mixture of quick shots of interesting-looking things and a song that doesn't quite go with the action.
This isn't going to turn off anyone who was already going to buy the game, but I'm not sure it convinced anyone who is on the fence.