On the web, we work in a Linux environment with Apache and MySQL.
We work largely with our own Content Management tools, and also with Magento (for heavyweight commercial sites). When we need a blog we usually turn to Wordpress. (We did write a blog ourselves once, to get it tightly integrated with an existing site. Took three days. But it is usually quicker to install Wordpress.) We also have some experience with Simple Machines Forums, Elgg, Joomla and Moodle.
In addition to blogs, Wordpress can of course be useful for other things, when used with the right plugins!