I'll kick off with the first blog that comes up on a search for "seo pr blog" in Google.

Really I shouldn't be recommending the Immediate Futures blog http://blog.immediatefuture.co.uk/category/seo-pr as it hasn't been updated since 29th November last year (come on guys!)

But - I've been to several expos where Katy Howell of Immediate Future blogs and she's an excellent speaker who has done some really good stuff....

Also - the big daddies of them all - the venerable Lee Odden and Greg Jarboe

Lee's Online Marketing Blog http://www.toprankblog.com

Greg's SEO-PR site with news updates http://www.seo-pr.com/

Any others you want to shout about?