There are so many factors that indicate lower oil prices for the short to mid term. This is worth reading. The Bloomberg article indicates a potential floor of $10! While I'm sure everyone, including the writer of the story don't expect to see it quite that low, there are plenty of reasons it could go south of $40.
At the end of the article Gary Shilling indicates his next article will discuss the winners and losers from lower oil prices. Here are some off-the-cuff educated guesses on who some of those winners and losers might be.
-consumers (not just of gasoline, but of any goods that require transportation)
-manufacturing entities and manufacturing-based economies
-bearish oil speculators
-any transportation industry
-America's trade deficit (i.e. it will shrink due to oil but that may be offset if imported manufacturing is boosted by demand)
-solar energy manufacturers like Solyndra (the ones that haven't already tanked)
-OPEC's smaller players who have been cheating on production quotas
-the Canadian dollar and economy
-bullish oil speculators