I just received my copy of "Collective Intelligence" in the mail this morning, and immediately sat down and starting reading. I've been reading for the past several hours, non-stop. It's that good. Perhaps the best part is the chapter at the end of the book that neatly and concisely sums up all the major ML algorithms: neural networks, SVM, kNN, k-means, decision trees, Bayesian classifiers, etc. etc. This chapter alone is worth the price of the book. I only wish it were longer (and it's not a short book).