Update: Seems this is an improvement for many, but not a 100% fix. Mark wrote in to point us to the discussion happening over at the NotebookReview.com forums which, combined with your comments below, makes it seem like we're perhaps not done here just yet.
Update 2: Another update from John B. at Dell, indicating that Alienware representatives have started hopping into their UFOs and visiting the homes of affected laptop users, Whitley Strieber-style. No formal update to this (apparently less than comprehensive) fix has been released yet, but information retrieved directly from the users should lead to some final resolution. We hope.
Update 3: GIRs91MJ commented to let us know of a beta fix posted by Dell that supposedly goes a long way toward fixing the problem. You know what they say about beta drivers (unclean!) but if you're desperate for a fix, give it a go.