Yeast, Malt, then Water. The latter is drier than a dromedary turd in Algeria, but contains a lot of good information. The hops book is very different in style and has less practical information than the others - throw it in whenever you feel like some light reading that is very journalistic/travelogue in style. I am only about a fifth of the way through Malt, but I like it very much so far - it seems to have a good balance between practical advice, history, and science.
Edit: As far as changes in my personal brewing, I don't think there have been many - but I know understand what I do much better. I feel they have also prepared me to tackle a true technical brewing textbook, though I'll have to review that dreaded organic chemistry first....