There was post on HN of a blog post link which contained a list of all free machine learning/data mining books. Wondering, if someone can post the link to it. I am unable to find it through search.
If you can afford it (both financially and regarding math background), Bishop is a really great choice. Almost everything you need to know is in it. I have it and just love it!
But he goes quite deep in the mathematical explanations (which is a great point, there is no better way to learn and understand) meaning you have to be willing to work on your math for this book.
It depends on your math background, but I've found Yaser S. Abu-Mostafa's Learning From Data the best, although Christopher M. Bishop's Pattern Recognition and Machine Learning is the gold standard. ;-)