The Powell's Books Lost blog post for "Greatest Hits" is up, and there's a lot more going on than meets the eye.
It looks like we have some evidence that every time Des saved Charlie, he not only changed the future, but the past and present as well. Because first season, Charlie couldn't swim. Some real proof would be from past Charlie flashbacks; if he was taking scag and not wearing the ring, then we have something. "Fire + Water" complicates that, because in one flashback when he wakes Liam from a nod, it doesn't look like he is, and in the diaper commercial flashback he is.
And there's plenty in there about Tolkien, Nick Hornby and Kierkegaard. And little Lewis Carrol and Joseph Campbell thrown in for good measure.