Thanks to Dustin Wax for an excellent resource list on Lifehack.org, called "50+ Productivity Blogs You've Never Heard of Before (and about a dozen you probably have)". And double thanks for including me on the list (#18).
Though I was familiar with quite a few on the list, at least half of them are new to me - and after sampling about a dozen of them in the last 30 minutes, I like what I'm finding on his list.
Check it out and go exploring. You can also see Dustin's personal blog at dwax.org.
[Update: Dustin has just added an OPML file that you can import into your RSS reader that will automatically add 62 of the 65 named sites - talk about easy! Just scroll to the bottom of the list and look for the link to the OPML file]