For some reason I like to read about St. Gemma the most. I can't say there is any biography I know of that stands out in terms of its writing or anything, but she fascinates me. No, not because of her looks, get your mind out of the gutter. There is some kind of significance to her life that hasn't been uncovered yet. She is a kind of suffering soul like St. Pius X, in fact, she died just a few months before his pontificate began. I don't know what this means but it means something, in my opinion. Her suffering is mystical, hypnotic to read about. She was a brutalized virgin, and her life has at least a little of the same kind of awe-inspiring combination of innocence and strength. She suffered constant illness, bleeding from the head, attacks from Satan, spiritual desolation when she was near-death like Christ on the Cross, and on and on.
Her life is a little morbid -- on the surface, she of course experienced great ecstasies at times -- and maybe that appeals to my sense of Spanish gloom. It wasn't about doing great works, it was a sort of private, secret martyrdom that she went through.
Speaking of St. Pius X, though, I would love to read a really good book about what happened behind the scenes in his life, because I believe he suffered many things that are yet unknown, and he probably anticipated all of what was about to happen. But that era in Church history may always remain mysterious and hidden.