Danielle de Niese, who had her own TV show in Los Angeles when she was still a teenager, has grown into a lovely, alluring, gifted opera singer. The voice is substantial, her agility, impressive, her vibrato is warm and engaging. Hers is not a white, early-music sound, but she has the technique for all of early music's tricks: easy octave leaps, smooth legato backed up by excellent breath control, skill in rapid divisions sung without aspirates. She lacks the ability to sing absolute pianissimo--to spin a line in an ethereal way (as in otherwise fine versions of "Lascia ch'io pianga" and "Piangero…"). Her presence as a "performer" is vivid and intelligent. Semele's "Endless pleasure, endless love" is coquettish but warm; "Dolce riposo" from Teseo has just the right sense of desire; "Tornami a vagheggiar" from Alcina is splendid in its virtuosity. The famous "Da tempeste" from Giulio Cesare shows her at her best--here is Cleopatra finally feeling as if she's back in control. William Christie leads Les Arts Florissants in classy but spunky readings.--Robert Levine