Eight new films -- count 'em, eight! -- enter the box-office competition this weekend, each on more than 500 screens, which is likely a record. Box-office forecasters are by no means united on which film will come out on top, but the Sony vampire flick 30 Days of Night, directed by David Slade and starring Josh Hartnett and Ben Foster, is generally given a slight edge, if only because of the fact that it is opening in the most number of theaters, 2,855. Gone Baby Gone, directed by Ben Affleck, is also expected to make a strong showing. Both films are R-rated, as are two other dramas, Rendition, with Jake Gyllenhaal, Meryl Streep and Reese Witherspoon, and Things We Lost in the Fire, starring Halle Berry and Benicio Del Toro.