On the album, Kat's voice is pleasant, aided by whatever programs that make average singers sound okay. On Home, her voice is down right soothing. On Idol, she often sounded like a screechy, er, cat in heat when she was made to sing songs far out of her range.
I will say her handlers did a good job of choosing songs that suited her paper thin vocals, it's just too bad those songs are so forgetable. Katharine McPhee should be singing jazzy, torch song type stuff, not typical, boring crap that you would expect a Brooke Hogan would sing. Perhaps that will happen once she gets away from the AI/19 Entertainment machine.