Probably the most popular WordPress Administration theme, the WP Tiger Admin by Steve Smith of Ordered List has been redesigned and updated for better 2.x compatibility.
A complete redesign has pushed WordPress Tiger Admin into version 3. It boasts a more streamlined design, better plugin compatibility, and general all-around goodness.
If you’re wondering, I’m not planning on continuing with the old design. It’s hard enough keeping up with the changing markup and popular plugins with one design, let alone with two. Although I won’t be updating them, I have posted links to the older versions on the plugin page in the version history.
I liked the older design, but I think the newer design is still better than the stock WordPress Administration design.