Duplicate content is penalized in one way or another all over the web, people do not like it, and hence search engines do not like it! Yet we all seem to promote it when we are posting to directories.
How is that?
With the exception of the king of duplicate content (The ODP and it's clones) there is one thing that we can all do to help out ourselves and the directories we post too. And that would be to mix it up a bit!
Your anchor text, will likely need to remain the same, after all, your site name is likely not going to change anytime soon... but the rest of the submission can be changed!
Tags: Many directories allow keywords to be added, rather then using the same handful over and over, mix it up a bit. Use 3 or 4 on this directory, and 3 or 4 different ones on the next.
Description: Rather then using the same description over an over, tweak it out, re-write it, come up with something different! Even if you just have a small handful of them, rotate them when submitting to the various directories.
Deep links: yes, yes, you may want to really push this or that page on your site in this manner, but why not mix that up as well? By promoting more then one page it increases your chances of finding people interested in your overall content...
Why is that?
To fight duplicate content of course!
There are two types of people in the internet world of webmasters, those that submit to directories, and those that do not. Most of the ones that do submit the same thing to every directory they go to submit too... what does that matter? Well, if you all are submitting the same content to the same directories, then what does that leave? Well, it leaves hundreds of directories with the exact same thing... your site and the sites of the others submitting to directories!
If you all start mixing it up a bit, then each and every directory out there will be just a little different. That makes people happy, and that makes search engines happy!
Even if you are only rotating the same four or five changes throughout your submission process, the chances of every webmaster putting their same four or five changes on the exact same directories is rather small...
So go on, mix it up a bit... the directory world will be a FAR better place!