This post can now be seen at http://www.linkspiel.com/2008/06/is-that-directory-worth-submitting-to/
1. Is the directory page your link will sit on in the index of G and Y?
If the page your URL will be added to doesn't show up in the index, then it does you no good ranking wise. Then you have to decide if the traffic alone is worth it.
2. When was the page last cached?
If more than a couple weeks, you need to check for exclusions and nofollows. Or ask why. Or just move along.
3. Does the page have more adsense ads than submissions on it?
This is a particular pet peeve of mine. I don't think I need to compete with adsense ads when paying for a listing. If there's as many ads as submissions, I walk.
4. Does the directory allow you to deep link?
Linking to your main dot com is good, deep linking is better.
5. Does the directory allow you to use your own Title?
It's more advantageous for me to use "Link Building Firm" than Alliance-Link in my submission Title if I'm linking for rank. On the other hand, a handful of links with my company name doesn't hurt either.6. Does the directory offer a lifetime link?
This is personal preference but - pay it once, be done with it, move on. If you go the annual route you may be asked to pay more the next year. My exception to my lazy-pay-it-once rule is Business.com
7. Is the directory listed in the Google Directory and/or the DMOZ?
http://www.dmoz.org/Computers/Internet/Searching/Directories/