Actually, aside from the first Matrix, this is the first Keanu "big budget" movie that I've enjoyed. Normally I'd prefer seeing him in older stuff like Bill & Ted, or My Own Private Idaho because it's early in his career and you can excuse the bad acting. But Constantine did a great job of covering that [the fact he STILL hasn't improved in acting skills] up for the most part. I think the secret is more one-liners and less monologues.
But yeah, Constantine, definitely good shit. It's already on my wishlist.