I'm very interested in what books are recommended, too.
I have the Norah Hunter book, as well. It was our main textbook for the floristry course. A bit outdated, but it covers just about every aspect of design, history, and a bit of business. I've flipped through the AIFD book -- IMHO, get one or the other.
On my bookshelf, ones that I'd also recommend are:
The House Plant Expert, by Dr. D. G. Hassayon, a fairly comprehensive and comprehensible book on flowering and green houseplants.
The Floral Artist's Guide - A Reference to Cut Flowers and Foliage, by Pat Diehl Scace. This lists a huge variety of floral material in point form, each with a picture, gives the latin & common names of each, what it's botanically related to, availability, colour range, characterisics, design applications, and vase longevity. Comes with a CD for the computer.
Cut Flower Care & Handling, from the Chrysal people. As far as I know, you can only get this by signing up for their on-line course at pokonchrysal.com (which is worth the effort).
A book that I recently got but have not had time to explore thoroughly yet -- Natural Flower Design - New Techniques and Design, by Aad Van Uffelen -- looks very interesting. I'm not thrilled by the finished arrangements, but the illustrated techniques and mechanics look very interesting.
Gregor Lersch's newest book -- can't give the title because everyone else at the shop has borrowed it. The arrangements (constructions?) are fabulous, of course, and it has detailed information on the mechanics he uses. This one requires a lot of study, however.
For eye candy and inspiration, I have Paula Pryke's Flower School, and two Straight From the Heart books -- the sympathy collection and the wedding collection. I prefer the sympathy one.