http://www.all-blogs.net/ http://www.bloguniverse.com/ http://blogflux.com/ http://blogs.botw.org/ http://www.geekyspeaky.com/links/ http://www.blogpulse.com/ http://www.blogrankings.com/ http://www.blogdup.com/ http://sportsblogs.org/ http://www.blogsweet.com/ http://www.blogtagstic.com/ http://www.findory.com/blogs/ http://www.bloggernity.com/ http://www.bloggeries.com/ http://www.weblogalot.com/ http://www.lsblogs.com/ http://www.blog-search.com/ http://www.bloghub.com/ http://www.blogwise.com http://www.blogarama.com http://www.blogtopsites.com http://www.topblogsites.net http://www.bloogz.com http://www.top100bloggers.com http://findingblog.com http://www.globeofblogs.com http://www.iblogbusiness.com http://www.industry-blogs.com http://www.theweblogreview.com/ http://www.bloglisting.com http://www.bloghop.com http://www.blogcatalog.com http://www.blogdigger.com/ http://www.britblog.com/ http://www.getblogs.com/ http://www.delightfulblogs.com/ http://www.blogroll.net/ http://www.bestblogs.org/ http://www.bloghints.com/ http://www.blog-watch.com/ http://www.blogbunch.com/ This list of blog directories can definitely improve your search engine rankings and boost your traffic get more of these in this 31 days guide.
There are more blog directories in the second column - http://www.rss-specifications.com/rss-submission.htm
Does it improve the ranking for your site or blog ? I had used some other directories but did not get much help in terms of ranking.