Summit Entertainment's Twilight took a big bite out of the DVD market last week as teenage fans of the movie grabbed up most of the 5.2 million copies of the movie that were sold, making it the year's top seller, according to Nielsen VideoScan First Alert. Some 3.1 million copies were sold on the first day, with many of the movie's stars and the director showing up at parties staged by retailers in key markets. Video Business magazine reported that Wal-Mart, the nation's biggest DVD retailer, set a company-wide single-day DVD sales record, and that parties at some of its stores attracted more than 1,000 fans.