I've discussed my thoughts on keyword density and the importance of a news article's title, but I haven't discussed the two together, so here goes. I don't use any particular goal for keyword density, but if I am writing about a popular topic, I do pay attention to what the popular keywords being used by readers to find information about that topic are.
If I were writing about Donald Trump taking two tries to produce his actual birth certifcate, I'd look on Google and see that "Donald Trump birth certificate" is a popular choice for people searching for this topic. based on that, and because it is precisely related to the content I'm writing, I'd make sure that Donald Trump and Birth Certificate were in my title. At Yahoo!, Yahoo! Contributor Network, Examiner and many other sites, the first part of your title ends up in your article's URL which can help with search engine placement as well.
I would also make sure that the first paragraph of my article clearly tells the reader what the article is about, and I'd include those words early in the paragraph. There would likely be words in between "Donald Trump" and "Birth Certificate" because that's not a natural phrasing.
The first sentence might be something like "Real estate mogul, reality TV star and presidential candidate Donald Trump was able to produce an official birth certificate a day after mistakenly attempting to pass off a hospital issued document to reporters at a press event."
Thereafter, however, I would tend not to use the full name Donald Trump. Instead, I'd use Trump as in "Trump displayed the erroneous document while proclaiming the ease with which anyone can get their official birth certificate." I'd also use descriptors such as "The flamboyant Atlantic City casino owner has publicly considered presidential runs in previous election cycles as well."
Under the old keyword density paradigm, a writer might use Trump's full name every time they referred to him throughout the article. That would have an unnatural sound and seem awkward to readers. Furthermore, the term "birth certificate" would be used for every reference to the document. This repetition would detract from the writer's credibility.
When I read an article like that, even ones that I wrote, it sounds as though the writer's primary goal is search engine ranking and that conveying information is, at best, a secondary consideration. It certainly doesn't induce me to subscribe to that author's writings or to share the article with others.
With the tremendous influence of social media these days, by over-using keywords, you may be missing out the potential for your article to go viral and giving up more page views than you gain with top search engine placement. Don't ignore keywords and search engine placement, but don't let them ruin the reader's experience.