I've read all her books but Tipping the Velvet stays with me because I read it for uni, and the most recent ones the Paying Guests, The Night Watch and The Little Stranger. I loved TLS although I know it's a bit marmite for most- you either find it really tense or really boring!
I actually can't remember Fingesmith although I have read it and I own it too. I know I found Affinity a bit boring and they kind of flow into two as I read them one after the other a few years ago.
Might have another read.