I think the directories are getting little importance, however the directories that have good reputation and having higher page rank would worth for submission.

I totally agree with you BobChrist. It really matters where the link is "parked at" rather than quantity.

I have created my own directory which is being indexed with Google, so I suppose links there are useful.

a lot of those directories with the Higher PR are now paying directories. I think getting into Free directories that are just starting to build may be worth it, because if they develop into high PR directories and you were in it when it was lower, and they didn't charge, it might benefit you long term.

hey ... its quite right that submitting site to directory for a same theme or niche is quite gaining in terms of pr .. but you should also think about other options like social bookmarking , press release , article submission sites. As only directory submission is just a one factor of increasing a pr or getting inbound links or visaversa

Any good press release sites?

Results depend upon the reliability of the data. Also, you must select only the product relevant directories. Plz check the meta tags also, don’t keep too many. Directory submission definitely helps in PR improvement.

Agree with others, you should still be careful about which directory you submit to.

I think relevancy is everything.

Is relevant directories key, or just relevant categories within a directory?