So many directories appear to have been penalised ...

I would create as many backlinks to your website using your anchor texts of your keywords as possible. Submitting to directories is still positive and there are many lists out there with high page ranking directories to submit to. The search engines love backlinks and submitting to directories, forums, blogs, articles, social sites give your website a presence on the internet that the search engines love. So the answer is yes, keep submitting and your website will increase traffic

If it doesn't take that long, and is free, then you have nothing to lose. No one really knows what Google values and plans to do.

Try this new site, you can have a permanent one way link in a PR6 Directory for as low as $1.
(No reciprocal link required and do-follow tag)
http://ez2find.com/

You should submit your site in more relevent category in the directory. Try to submit your site in best web directories like search.eilon.com. it is best USA web directory and search engine....

Search engines still love back links. The importance of backlinks is not yet got down & the first step to increase links is web directory submissions .
Of course it is worthwhile submitting to directories. Google is tracking paid activities through directories, & may be some of those get penalized. But free directory submissions in directories that are genuine and spam free still have their value. So "Keep submitting" :)!.