Recently, I thought it would be nice to have a syntax highlighting feature if you present code snippets - you might know this behaviour from your code editor. I found two WordPress plugins, but unfortunately, I did not quite manage to make them work in the right way:

• “Highlight.js”: softwaremaniacs.org/soft/highlight/en/
  This solution is based on JavaScript in combination with CSS. There is also a WordPress plugin available, but I somehow didn’t succeed to integrate it into my own stylesheet - it just wouldn’t look right.
• “WP-Syntax”: wordpress.org/extend/plugins/wp-syntax/
  This WordPress plugin uses GeSHi, the “Generic Syntax Highlighter” which is based on PHP. It works OK when you have the WordPress visual editor deactivated - otherwise, it will replace “<”, “>” and “&” with the HTML-entities which does not look nice in a code snippet.

I must admit: I didn’t try TOO hard, because the amount of code snippets in my blog keeps within reasonable limits.