There are quite a few good 'mini-stories' in The Silmarillion that'd make fine films. Beren and Luthien, for example. On the one hand, they're an epic romantic couple; on the other hand, they're badass warriors who skin vampires and wear their hides as disguises. Then there're all the legendary champions of the first and second age - like that Elf whose name I forget, who defeated the Balrog king in single combat. There's also room for arching, connecting narratives - the golden age and then decline of the Elves, and their conflict with the Dwarves; the flourishing and eventual decline of Numenor (which'd be great for a film/series covering the events leading up to LotR).

But I agree, it'd be hard to make all of this into coherent, compelling tales. TV could work, and the fantastic BBC/HBO series Rome shows how years of history can be adapted into utterly riveting drama - but the scale of Tolkien's imagined world almost seems like it'd lose a lot in the translation to the small screen. We'll see, though...