Saw the movie in Mexico after you suggested it, it ROCKED! The DVD is on sale, has 18 minutes of additional footage, PLUS an alternate ending they were toying with before release! Keanu Reeves was the perfect choice for Constantine, IMO... It also deals with the conflict between angels and demons, and some angels that have ulterior motives.
The free Stealth preview has lots of footage, interviews, PLUS previews of Zorro, The Da Vinci Code, and more. It also has trailers for XXX:State of the Union, Guess Who, Steamboy, and more...