My favorite way to find quality blogs (and books and movies, for that matter) is via recommendation. Towards that end, I thought I'd share a PPC Blog  you might not be reading (every so often we share a list of our favorite search and online marketing blogs ).
Aaron and Giovanna Wall of SEO Book  fame (see our SEO Book review here ) have started collaborating on a sister site that focuses on PPC. The content is really strong, offering a very similar level of high quality how-to and industry trend material. They recently launched a very clever AdWords tax calculator  that can help give you an indication of how much you might be wasting on paid search.
Here is some of the content they've churned out so far:
- A PPC Copywriting Guide 
- A Post on Leveraging Search Query Reports  (Though of course we all know the best way to leverage search query data )
- A Guest Post on Our Free Tools Around the Time of Their Launch 
- A Cool Post on Leveraging the Wonder Wheel for Campaign Structure 
If you haven't already it's definitely worth checking out and subscribing .