I recently got Object oriented Programming with Actionscript from Branden Hall and Samuel Wan and highly recommend it. This is a must have for any Flash developer that wants to get serious with OOP and reusable code in Actionscript. Worth every penny!.
Also here are some designer related books:
MTIV: Process, Inspiration and Practice for the New Media Designer
by Hillman Curtis Publisher: New Riders
Fresh styles for designers
by Curt Cloninger Publisher: New Riders