The American Ballet Theater version of the Tchaikovsky classic, a 1977 studio rendition directed by Tony Charmoli, has become a holiday perennial on PBS stations and home video. It's a favorite of parents who want to give their kids the gift of culture--and with good reason. There's a loose fairy tale plot to keep dance neophytes interested, and Boris Aronson's eye-candy production design is a series of lavish dioramas. From an imperial-era Russian Christmas party out of Tolstoy, a young girl named Clara (Gelsey Kirkland) is whisked in dreams to an imaginary world populated by the animated creations of the wizard toy maker Drosselmeier (Alexander Minz), who prances on his stick-thin limbs like a Dickens illustration come to life. The main attraction is, of course, Mikhail Baryshnikov, one of the greatest classical dancers of the century, at his absolute peak of athleticism and precision. An opening slow-motion montage diagrams his fabled smoothness of execution, elegant airborne trajectories that have a feather-light perfection. 79 minutes, color