Looked at Jeepers Creepers again, and well, I think it's the best American horror picture I've seen recently--which may reflect more on the quality of recent American horror than on the movie's actual virtues. Salva's Powder was an unappealing mess, a sentimental plea for tolerance that you can't help but feel is self-serving (and if you feel that, you can't help but note that the lead is not just pale and beautiful and half-nude much of the time, but also possesses supernatural powers).
Jeepers Creepers works because Salva takes the premise of Powder and flips it around: this time you feel he's the monster, and this portrait of a super-powered serial killer as sexual predator pretty much fits what little you know of Salva (filmmaker (with attendant powers) as convicted sexual predator, reformed (or so they say)). That a director is so willing to take his image and push it as far as it can go is as disturbing as it is effective.
And Salva pushes it pretty far: the opening sequence, revolving around a huge pipe diving deep into the ground, with unspeakable smells emanating from it (Got it? Got it?) and unspeakable secrets lying at the other end of it; the use of beautiful young men to play the Creeper's victims; the occasionally breathtaking image (the shot of the Creeper carrying away his victim in the light of the full moon); the final scene (SPOILER), with its metaphor for anal rape pushed to an extreme (the rapist has literally gotten inside your skin, and done so with much screaming and agony).
Perhaps what makes Salva really unsettling is that he is not without some talent, and here he is, indulging them and his obsessions for your pleasure and entertainment.