No question: "This Delicate Thing We've Made" by Darren Hayes. It's 25 songs worth of pure awesomeness. It makes me happy: creates that rare moment of perfect, mindless joy. Not many things are able to obliterate reality so completely.
The songs string together to tell a story, Darren goes back in time in a quest to fix the pain in his past. But during the journey he loses his way, relives things he would have rather never remembered, ends up in Victorian England, makes a stop or two in the future before finally coming home to his 'fella', knowing that the past can only be changed in the present, and the present is just the way he wants it to be.