Moody, melodic, muscular--Sarah Vaughan's voice has long enjoyed a niche of its own in mainstream jazz. Her interpretations tend to display the same regal command whether the musical backing is a three-piece combo, a 25-member big band or a standard studio string orchestra. On "The Best of Sarah Vaughan," a collection of Vaughan favorites recorded in 1978-79, there's a fine selection of all these, and most of them find Vaughan truly at her best.

"I Gotta Right to Sing the Blues," "From This Moment On" and "Ill Wind," all backed by Count Basie's orchestra, along with the studio rendition of "In a Sentimental Mood," are the most satisfying tracks. These are the songs that Vaughan has made her own, and with which her following most identifies her. Those who found Rickie Lee Jones' recent interpretation of "Lush Life" heretically idiosyncratic and self-indulgent will undoubtedly take solace in the version provided here, with its broad-ranged adherence to melody over emotion and its uneccentric, almost unsentimental nostalgia.

The worst of this "Best of" is Antonio Carlos Jobim's "Dindi," which was recorded in Rio de Janeiro with Brazilian guitarist Helio Delmiro. Right idea, wrong artist. Vaughan's deep, sinewy vocals and forceful vibrato overpower Brazilian jazz, whose light, poppish progressions call for a breathier, more ethereal style a la Michael Franks or Kenny Rankin. Chafing under the weight of Vaughan's complicated phrasing, the musicians sound as though they're preparing to jump off at the nearest key change. SARAH VAUGHAN -- "The Best of Sarah Vaughan" (Pablo 2310-885). Appearing Friday through Sunday at 8:30 and 10:30 at Charlie's Georgetown.