Some Good posts on Blogging tools and widgets

Read/Write Web talks about how to use widgetbox to add widgets your blogs, it also lists the top 5 widgets for the year 2006
Read More...

Widgetbox has lot of widgets here are the numbers by category

• Blogosphere -118
• Communication - 45
• Fun and Games - 70
• Interests - 72
• Information - 112
• Media - 74
• Money Makers - 27
• Other - 45

Thats lot of widgets created by widgetbox and other contributors.

There is also a old post on Quick Online Tips which is supposed to be updated periodically lists 14 essential tools for blogging including Technorati, Mybloglog, AdSense and Haloscan for trackbacks.
Read More Here ...

Pro Blogger gives big alphabetical list of all the tools which include tools for posting a blog, tools for offline editing blogs etc.
Read More... Here

Update
Widgetoko is another good site which keeps reviewing widgets for the blog.

Update
Thanks to Howard Lindzon here is another good blog, Widgets Lab maintained by Derek Anderson.

Update
Avinash writes on blogging tools from his experience - Blogging: How-to's, Technical Tips and Best Word Press Plugins

Update
Improbulus writes about new blogger page layout management - New Blogger: page elements widgets code reference and tutorial

I will periodically update this post, as and when I get good links