Code syntax highlighter using Google Prettify, supporting the HTML5 recommendation, and caching plugins.
I like this so much, I've added it to my list of the "Top 5 WordPress Plugins for Coders"
The most complete Google Code Prettify plugin I tried.
Good plugin using Googles framework that is compatible with the highly recommended and sort after W3Cache plugin.
It does what it says.
This plugin is simple to use, the highlighting looks quite good, and the formatting is easy to customize (assuming you know some basic CSS). The plugin also includes support for a wide variety of languages.
I can be biased though...