You say:

"Click the Down Vote button only if the post is disrespectful, rude, vulgar, or in general drags down the level of discourse on the boards. Don't use the down vote button just because you disagree, you think the post is "stupid," or you don't like the poster. Only down vote a post if a user is being a bad member of the community. "

If I vehemently disagree with a post or think it's dumb, but it doesn't meet the criteria you list above, it would be useful to have the option of a "soft downvote", where we can voice displeasure with the content of the post without suggesting the poster is a bad member of the community. Rather, he's just a guy with bad ideas or insights.