Ezine
Buzzle
The Free Library
Articlesbase
Articlealley
Articledashboard
Goarticles
Isnare
Amazines
About.com

These have the highest PR and give the best results on a consistent daily basis :-)

Oh yeah, change em for each directory, the more original the better, TRULY !!! You WILL see a difference.

The answer is that it depends entirely on the goals you have in mind for submitting to article directories to begin with.

For purely backlinking purposes, I'd say submit to the sites with the highest PageRank first. Here is a list of article directories and their respective PageRank (bear in mind this is for the homepage only, not any/all individual article pages - but it does "trickle down"): List Of Top 50 Article Directories By Traffic, PageRank

If, on the other hand, you are utilising an article directory for its original / traditionally-intended purposes - that of widespread article distribution - then EzineArticles is almost certainly the main directory you need to be submitting to, since this is one of the few directories that webmasters / publishers actually trawl through when looking for content to publish on their sites.

EDIT: In response to the suggestion given by the above poster to write / rewrite original copies of an article for submission to each directory, I will respectfully disagree.

When submitting articles for backlinking purposes, for example, there is simply no need to rewrite a unique version of the same article for each individual directory; each copy of the article, subject to be crawled/indexed by Google, should still go towards your backlink count, and pass link-juice. The only time you might need to do this is if you're trying to dominate / populate the search results for similar articles targeting the same keyword phrase(s), since Google doesn't like to display too many instances of the same articles for any given search term, out of an interest in providing results diversity.

Thank you for the advise and directories,much appreciated!!

Werna