A career highpoint for Debbie Reynolds, The Unsinkable Molly Brown is essentially a showcase for the diminutive star's singing, dancing and acting. Not that she's the only thing in the movie. Harve Presnell is very definitely a big presence -- and his luscious, booming baritone with its sweet, light upper register is very definitely a tremendous asset. Presnell shows his voice off to good advantage in "Colorado, My Home" and "I'll Never Say No," two of the more attractive offerings from Meredith Willson's good-but-not-great score. The leading man is also a decent actor, much looser and more engaging than other such singers in the Howard Keel mode, and he partners Reynolds well. Reynolds gives the part her energetic all, plunging into the raucous aspects of her character with wild abandon, and making the transformation to elegant swan believable. At times she does try too hard, and the push is evident in vocal strain in her two big numbers, the anthemic "I Ain't Down Yet" and the boisterous "Belly up to the Bar, Boys." And even with all her commitment and enthusiasm, Reynolds can disguise neither the fact that Molly's singleminded social climbing has an unpleasant aspect to it nor that the plot is often thin and unconvincing. Charles Walters has shot the film beautifully, and the physical production is impressive. While Peter Gennaro's choreography is of variable quality, the ensemble -- including stellar dance talents such as Grover Dale and Maria Karnilova -- is first rate.