Welcome to the Q&A Forum

I like Seo RoundTable from Barry Schwartz and also some of  those already list above especially for up to the minute search engine changes and trials that have been seen. As per Egol's comment - I too have probably learnt more about SEO technique and current topics from the Moz Q&A than anywhere else. To the point where I am now vastly more confident in my knowledge of the area and can now try and help others.