Fluffy, frothy 'Razzle'; '42nd Street' dazzles; 'Within' needs elbowroom; 'Nightclub Cantata' merely survives

''42nd Street,'' David Merrick's Tony-award-winning musical that tapped its way into the Shubert last week, shines brighter than a new mint dime. This archetypal American success story - chorus girl catapulted into stardom when leading lady breaks her ankle - has all the essential elements of a hit musical: exuberant and precise tap-dancing, appropriately brassy singing, elaborate production numbers, and a plot that amiably lends itself to being burst into song.

Robin Wagner's sets and Theoni V. Aldredge's costumes are as dazzling as the cast. At one point, women in jewel-toned gowns pour out of a small entrance so fast they look like a multicolored scarf being pulled out of a pocket.

But the most endearing aspect of this show is the one thing you can't practice, daub on your face, or zip into - it's fresh, uncamped enthusiasm. You can tell by the eyes when they have it, and this cast has it. And that's what really lights up the stage.

''42nd Street'' will play through July.