I'll second Dilate. I also like Knuckle Down (2005) and Living In Clip (a live album).
She does several versions of Amazing Grace which are worth a listen or two. One is on Dilate and another on Living In Clip. Both versions are nicely irreverent. Ani has always done her own thing, and has kept her music away from the influences of producers by having her own label (Righteous Babe).
Although I like much of what she has produced, I have to be in the mood for her music. Thinking about it, I'm more apt to listen to her when I'm pissed off about something.
John