Christopher Walken as Gabriel in The Prophecy and its sequel does some of his best work ever. I know these movies got mixed to bad reviews, but I really like the urban fantasy story of angels warring with each other and humans getting caught in the crossfire. Walken is just great as Gabriel, a dark angel wreaking havoc on earth. Even when he has his trademark Walkenisms (awkward pauses, stuttering, random high voice inflection on words), he still brings menace and intimidation to the role, and makes him both evil and sympathetic at the same time. I think the first two movies are awesome, due to Walken's performance, the dark fantasy elements, and the solid casts.
The Prophecy movies, as they progressed, went from having a talented cast (the first movie had Elias Koteas, Viggo Mortensen, Eric Stoltz, and Virginia Madsen) to a marginally talented cast (the last movie had Kari Wuhrer, Jason London, and Jason Scott Lee). The second movie had Russell Wong, Jennifer Beals, and Brittany Murphy in it, and while they were more b-level, I still thought they were all good in it. I even appreciated how the heroes were racially diverse (Beals' character is Hispanic; Wong's character is an angel, but played by an actor of white European and Chinese descent). Walken just delivered a great performance in these movies, even if they were seen as low-rent dark thrillers about angels warring with each other. He is fantastic.