The list of women who can sing better than Diana Krall is LONG. But she's a pretty good pianist and the production values on her albums are usually stratospheric. You just need to listen to Quiet Nights - my hi-fi loves that album. And the songs on The Girl In The Other Room are well composed, with good lyrics (written by hubby Elvis Costello, I think). I have DVDs of her Paris and Montreal concerts, and she does well in a live setting. Her sense of timing is good, and she has enjoyably dry sense of humour. And, of course, she is a FOX.
But I stand by my first point: she is far from being a great singer. Rather give me Sarah Vaughan, Dinah Washington, Anita O'Day, Betty Roche, or Julie London.