Technorati is one of the coolest sites on the Internet.
http://www.technorati.com/

This is a very good tool for promotion.
http://www.icerocket.com/index

This will get you tons of exposure.
http://blogsearch.google.com/

This is the best site for free promotion of your blog that I have found. Very well done, solid community, great people.
http://www.blogcatalog.com

http://www.alltop.com

This site is VERY well done. Excellent graphics and solid results.
http://www.blogflux.com

This is a cool, well designed site that lets you submit your blog.
http://www.blogarama.com/add-a-site/

Very smart site with a great design and functionality for submitting your blog.
http://www.bloglines.com/