CLASSICAL. The Benedictine Monks of Santo Domingo de Silos: Chant. (Angel Records): It may seem odd to market 1,500-year old Gregorian chants in the age of Madonna. The monks of Santo Domingo's album, ``Chant,'' with its hip, Magritte-styled cover, has topped the charts in Europe for months and is just now hitting America. The monks' antecedents were folk who really valued the Word: Rather than wedging words into a rhythmic or melodic format, they allowed tunes to wander around like a stream that works its way to the sea. The effect is exhilarating.