THE PENGUIN GUIDE TO COMPACT DISCS AND CASSETTES by Ivan March, Edward Greenfield and Robert Layton (Penguin: $23.50; 1,417 pp., paperback original). In recent years, the Penguin Guide has become a basic reference for classical music fans. The three reviewers evaluate many--but by no means all--of the recordings of the standard repertory. Their tastes reflect a decidedly Anglophile bias, and their worship of Dame Janet Baker seems excessive at times. But classical CD buyers will enjoy agreeing or arguing with their assessments of conductors, orchestras and soloists.