dunno if its a great idea...
don't be too strict with all the anonymous posting, if you want to get a good working forum give guests permissions as well, preferable as much as possible.
when you get it running like you want, and it gets busy, then you can kick guests off some parts of the forum, or give em less permissions.
Not?

edit: owh, just read your reply jeff (same time as mine), if the buggers are bugging you, you have to stop it!