This was a fun movie. Lot of action, quite a bit of violence. Lead actress, Kate Beckinsale, was quite nice. I think the amazon.com review said it best by describing the film as a "cuisinart movie (blend a lot of familiar ideas and hope something interesting happens)" -- who could argue with the accuracy of that review.
This film was basically Blade 3½, but with a female. Blade 4 is actually set to be released in the next year or so. How original. I'll go ahead and get all prophetic by saying I believe the film will involve Wes Snipes killing vampires with a big sword and some guns. We'll see.