T1 is a Tumblelog style theme that has been updated to support WP 2.3's tagging feature.
If you don't use tags or WP 2.3, don't worry. This theme still works great.
Check it out with a live demo at:
WordPress 2.3 Tag Support
8 Default Categories
Extremely Simple to use
Content focused with individual category styling. One of the few "Tumblelog" themes available for WP.