Wiseguy on CBS

A compelling Stephen J. Cannell drama about undercover FBI agent Vinnie Terranova, who tries to infiltrate organized crime after having served time to establish his credibility with the underworld. The show pioneered the use of multi-episode arcs, and was less a standard cop drama than a string of first-rate miniseries about the seductiveness of evil, thanks to some memorable villains (including Kevin Spacey and Joan Severance as the gleefully sinister Mel Profitt and his sexy sister Susan).