I’m using the free blog system WordPress. So far I’ve tried a lot of these systems, and WordPress is by far the best one. It’s incredibly easy to install and configure.
I’m using the following plugins (not up-to-date at the moment):
Feedburner Feed Replacement – Forwards all feed traffic to Feedburner.
Similar Posts – Displays a list of posts similar to the current one by comparing the way they use words.
Ultimate Tag Warrior 3 – Add tags to wordpress (tag cloud in sidebar).
WordPress Database Backup – On-demand backup of your WordPress database.
WP-Cache – Very fast cache module.