These blogs and sites range from strategy, SEO, design, development and more.  Here are a few (in no particular order) you should add to your regular reading:

Seth’s Blog (Seth Godin)
AdFreak (AdWeek)
SEO.com (SEO.com)
How to Change the World (Guy Kawasaki)
TechCrunch (TechCrunch)
jQuery.com (John Resig and the jQuery Team)
W3Schools.com (Refsnes Data)
Creativity (Crain Communications)