Mollom

Make spam go away! This is a great service that is free for a low traffic site. A great anti-spam solution for Drupal! Also check out Honeypot and the Bad Behavior module.

http:BL

From the project page, "Implementation of http:BL for Drupal. http:BL can prevent email address harvesters and comment spammers from visiting your site by using a centralized DNS blacklist. It requires a free Project Honey Pot membership. This module provides efficient blacklist lookups and blocks malicious visitors effectively.

Common HTMLawed settings

Here are some common settings for HTMLawed that can be used as a more lenient 'filtered html' format for trusted editors that need a simple WYSIWYG. This configuration allows images, which can be a security risk. If you don't understand the risk, then leave Drupal's defaults the way they are and perhaps try to work with the Full HTML format or use CSS classes and stylesheets.