"EVERYTHING today is effects and staging at the expense of lyrics and book. All this 'Cats' and 'Evita.' They call it a concept musical," laments composer/singer/pianist Arthur Siegel about what he sees as the decline of the classic Broadway musical. Siegel, who has written songs for Hermione Gingold, Gypsy Rose Lee and Kaye Ballard, will perform the show music of Jerome Kern at the Wolf Trap Barns tomorrow and Saturday with singer Sandy Stewart. The act includes an impish "medley of his hit," which was "Love is a Simple Thing" from the Broadway revue "New Faces of 1952." Siegel is at work on a new musical based on the comic strip "Nancy." He picks his five favorite Broadway musicals:

1. Lady in the Dark, music by Kurt Weill, lyrics by Ira Gershwin: "It starred Gertrude Lawrence and was Danny Kaye's first big Broadway break. They did things with that show I never dreamed could be done on a stage--it was like a movie!"

2. Follies, music and lyrics by Stephen Sondheim: "Startling, thrilling staging techniques. It felt like it was the end of an era--in pastiche form, it captured all the old musicals within a contemporary musical."

3. Gypsy, music by Jule Styne, lyrics by Stephen Sondheim: "My favorite for sheer musical comedy. Ethel Merman was the Laurette Taylor of musical comedy. She reached a depth of dramatic portrayal you rarely see in musicals."

4. Company, music and lyrics by Stephen Sondheim: "A perfect gem, the most integrated musical. Nearly every song stopped the show, which surprised me. I didn't think they could do that in this day and age."

5. Carousel, music by Richard Rodgers, lyrics by Oscar Hammerstein: "Probably the most representative Rodgers and Hammerstein musical, and it showed the maturation of the form. It's Rodgers' best score--he did so much with waltzes and the symphonic suite of carousel music."