ACCORDING TO WYNTON Marsalis, jazz "places a premium on originality and individuality." Personal style has always has been a key element to the genre, to the music itself and beyond. "When people dress well, they play well," said Mr. Marsalis, 51, in an interview at the gleaming new offices of Jazz at Lincoln Center in New York (JALC). He added with a laugh, "My thing is if we don't sound good, at least we look good." To ensure the latter, he's got a wardrobe of natty suits, and wore a Brooks Brothers gray pinstripe three-piece to our interview (Brooks is the official clothier of JALC)....