Hah. This random internet stranger would like to say she is of the opinion that there /is/ no one best book of The Dresden Files (because they're all great). On the other hand, if you're a big time Thomas-fan, Blood Rites may cause you to make some noise while reading it. (I don't want to spoil anything, so I'll keep it vague like that.)

*might have replied to some other aspect of your post but got distracted by the shiny mention of The Dresden Files*