It's Friday night, and the ticket-holder line stretches around the block. Latecomers can forget it; the 8 p.m. show is sold out. The lobby's abuzz, as vintage-clad hipsters, film students, and cineastes just off their day jobs rush to buy organic popcorn, Jacques Torres chocolate bars, and David Lynch's "Signature Cup" espresso before the show. It's a familiar scene at Manhattan's art-house theaters. But this snapshot of exuberant cine-mania belies gloomier truths about the current state of New York's art-house marketplace. Anthony Kaufman reports.