Yes they are worth it just combine them with other SEO methods (unique content, article marketing, forum signatures, blog commenting, social bookmarks etc)
they sure are i have one article, wrangle it and submit it to the different directores so each one is unique and works a treat!
I am doing directory submission from the last couple of month and think have submitted to almost 1000 directory with the PR ranging from 8 to 3. Do i need to submitted my site to more directories or there are any other contemporaries which i can look for further boosting the online presence for my sites.
Yup they are still worthwhile. But alone they cannot help you in increasing your pagerank and you need to go for some other SEO methods too.
Is submitting to lower rank directory would be a wise thing to do? I fear of passing to pr to this lower ranked directories while submitting my url with them.