I just got my copy of Score! last week, can't wait to dive into it. I'm a big fan of Kevin MacDonell's blog (don't judge him by the most recent post, it's a lot more technical than he normally is). Also you don't have to be a CASE member to purchase the book, you just have to have a login to the site which you can get free.
I have been drawing on Birkholz's book for our data visualization product, coming soon!
Score! - Data Driven Success For Your Advancement Team - By Kevin MacDonell and Peter Wylie. Seems to only be available via CASE at the moment. I read this one. It was approachable and well-written, but I'm still not sure if I understand exactly how to pick and test the correct fields for scoring. Will need to reread after a bit.
Fundraising Analytics: Using Data to Guide Strategy - By Joshua M. Birkholz. Also pretty good, though dry. The last few chapters walk you through using SPSS (Statistical Package for the Social Science).
Data Mining for Fundraisers - By Peter Wylie. Haven't read it yet... have a feeling this might help me find some correlation between fields (if I can understand it)...
What other books have you all read and can recommend?