Good to the Last Drop

Maxwell House has been using this slogan since 1915 (and it also been used by Coca–Cola). The coffee brand used to claim that the phrase was coined by US President Theodore Roosevelt, after he first tried a cup of its product. At one point they said they'd made the story up; but later advertisements have continued to refer to it. (See this 2009 example on YouTube, starring Roosevelt impersonator Joe Wiegand.)

So ... was is or wasn't it? I think the answer is, nobody really knows. You can read more about it on Wikipedia, or this Culinary Lore blog.