The Readability Bookmarklet has taken care of this headache for me. Save this bookmarklet in your browser link bar and click it when you want your reading to be a "clean" experience. It simply removes the clutter around the main body text you want to read, changes to font to a larger, easily readable one, and provides a clean white background. I am not kidding, it makes a world of a difference. And not to forget, its a much cleaner format should you decide to print the article too. (Added benefit, you might save some trees by not printing the random junk a.k.a. ads, and banners etc)
You can customize your bookmarklet to show you your article in any of the following formats: Newspaper, eBook, Novel, and Terminal. It allows you to select your text size, and the margin widths. I suggest you check out the Readability experiment website, the video within, and follow through to the bookmarklet setup page. You wont regret it.
And now to show you an example, I am uploading a screen shot of the browser with a news article open on CNN.com. The first picture is the regular webpage. The second one shows what the Readability Bookmarklet does to enhance your reading experience.