Woman in White, just for the reason that it is the entire original stage show on the recording. Everything from the scene changes to the songs themselves to Angela Christian's random shrieking!
or if you haven't heard any of it yet, Jekyll & HYDE; Some will tell you the Complete Recording (with Anthony Warlow, Linda Eder & Carolee Carmello), but if you haven't heard ANYTHING of it yet, I'd probably buy the OBCR because Linda Eder, Christiane Noll & Robert Cucioli sound fantastic together. Or if you don't like Jekyll, buy the OBC of The Scarlet Pimpernel...and if you are a Rachel York fan than buy "The Scarlet Pimpernel: Encore" ("1999 RevivalCast"). It's always nice to hear something from all different composers!
But I really have no idea what your into. But you can't go wrong with Patti -- EVITA, Les Mis (London), Sunset Blvd. (London), Sweeney Todd (Broadway Revival)...all great recordings!
On the amazon marketplace get the 3 CD Show Boat box set conducted by John McGlinn, with Frederica von Stade and Jerry Hadley. This one is the original with all the liner notes. There are two listed as "like new" for about $17. shipping will make it about $20.
Well worth it. I bought one awhile ago and "like new" means just that. Show Boat