Just want to comment on the Tolkien bit: Peter Jackson's six-film adaptation of The Hobbit and LotR is, of course, far from perfect, but the story and scripts is pretty coherent, which is more than can be said of the Harry Potter films (especially PoA, GoF and OotP). You can make DVD documentaries of the Middle-earth saga with clips of the films put in, and you'll have pretty much everything you need (e.g. "If Bilbo hadn't spared Gollum that day" *clip of Martin Freeman lowering the blade* "No one would be there to fall into the lava with The One Ring" *clip of Gollum cradling Da Precious and falling*) at your disposal, but can you do the same with, say, the very important backstory of the Marauders bullying Snape, Snape turning evil but repented, while Wormtail was the real traitor and actually gave away the Potters' house? Post-CoS the films stubbornly stuck to linear-narratives (except for a few pensive scenes) while also SHORTENING the lengths. And it shows.

I envy the fans of shows and movies that can do that.