THE ADVENT OF DVD has been a boon to movie buffs and collectors. Unlike videotape, which can deteriorate with repeated viewing, dries out, and may snap if rewound too tightly or quickly, DVD provides fidelity of picture, excellent sound quality, and permanence, assuming that the discs are not carelessly mishandled. Moreover, the discs' ability to accommodate far more material than tapes do leaves room for special--and, admittedly, not so special--features, adding even further to the ...