Spiritual Midwifery- Ina May Gaskin (very crunchy....if you can get past the super hippie stuff like "and then things got heavy..." you'll love it!)
Ina May's Guide to Childbirth- a newer book. VERY good.
The Well Pregnancy Book- Mike Samuels and Nancy Samuels (my sister in law who had her kids 14 and 9 years ago at home gave me this book. its great!) I esp. like the chart in there where it says "body feeling during pregnancy.....cause.....remedy" Everything is easy to read, good pictures, lots of diagrams, and info. My book is from 1986 but I think its very informative!
Birthing from Within is OK in my opinion. A little too new agey for my tastes.
Baby Catcher- Peggy Vincent. (a good story from a midwives point of view).
The Happiest Baby on the Block- I liked this one too. but its about newborns....not pregnancy.
The Girlfriend's Guide to Pregnancy- Vickie Iovine. A VERY mainstream book. She sucks as far as homebirth, breastfeeding, etc. but I still like the book because it tells you stuff NO ONE tells you about having a baby. Humorous. Just don't give it to a friend, since a lot of the advice is bad. I just liked it cuz it was funny.
Other than that, I read books on vaccines like:
Evidence of Harm - David Kirby
and What your doctor may not tell you about vaccines- Stephanie Cave.
(again not about pregnancy, but good reading if you are thinking about those issues).
I also like the How to Talk to Kids so Kids will Listen, How to listen to kids so kids will talk books.
I have Wise woman herbal too, and its good..... although I get most of that info from my MW or MDC