Who gives a shit who "won"?
Nobody should care in the sense of caring who wins American Idol. On the other hand, it IS a reasonably interesting look at the two people who have by far the greatest chance of actually running the country. And if we're talking about "winning" in terms of who can articulate the best argument for their ideas, that seems important too.
Obama sleeping through the first debate was a great Republican talking point, but it was also important because it showed a President who seemed unsure of his ideas and his dedication to those ideas. Similarly, this debate was important not because I think Obama "won" in some superficial way, but because Romney expects us to vote for him for President despite putting on a 90 minute display on foreign policy at the end of which I have no idea what his foreign policy ideas are. He didn't "lose" because he didn't have better sound bites or because his demeanor was poor, because neither of those things were true. He "lost", IMO, because he wants to be President but can't be at all convincing that he'd handle foreign policy. On those grounds, the debate was extremely important...as the previous two debates were.