I love Claire Tomalin - the biographer. She writes as if she knows them and you get a feeling of very close intimacy.
There isn't much on Jane Austen but she still takes you into her world and by the end even though she's still a mysterious character - you feel as if you've been there with her.
Her biography of Samuel Pepys is also very good - and the first biography I had ever read. I can't say I'm actually that interested in biographies - most others I've tried reading seem to try very hard to be boring and stodgy. But Tomalin takes you on a beautiful journey.
I would like to read her Hardy one next.