I NEVER listen to a cast album before seeing a show and usually like to know as little about the plot as possible. It takes away from the fun of discovering the show in the theatre if you walk in humming the tunes. If the creative team -- book writer, composer, director, et al -- have done their jobs and crafted a coherent and interesting theatre experience, then I should be able to enjoy and appreciate on one cold initial viewing. If I can't and need to consult a cast album or reviews to understand any aspect of it before going in, then they haven't done their jobs.
"What a story........ everything but the bloodhounds snappin' at her rear end." -- Birdie
[http://margochanning.broadwayworld.com/]
"The Devil Be Hittin' Me" -- Whitney