The TinyMCE plugin that ships with Vanilla is a bit of a beast, and overkill for probably any forum software, where you just need the basics. No boot, the plugin is far from intuitive and difficult to configure.
This plugin hides the complexity and brings the simple options to the fore, shipping as standard with only a few simple formatting toolbar options as standard. It also allows the user to easily assign a stylesheet to the edit area to customise the look and feel of the text.
See it in action at xjsfl.com/forum/