Ari Stathopoulos

A clean, minimalistic administration theme inspired from the new customizer look of wordpress 3.4.1 
It’s pretty basic and adds a css file to your administration.
Since this plugin was created I have used the knowledge that I have acquired to build the bootstrap admin theme, which I would recomend you use instead of this one. 
You can get it here: https://wordpress.org/extend/plugins/bootstrap-admin/
This project was built for the http://magazi.org network of stores.

Magazi Admin Theme

A clean, minimalistic administration theme inspired from the new customizer look of wordpress 3.4.1

ryansommers

Slate provides a clean, simplified design for your WordPress Admin area.
Our goal was to simplify the visual design with a primary focus on the content writing experience.
If you like Slate, please consider leaving a review here on WordPress. Thank you!

Slate Admin Theme

This admin theme is particularly well thought for High resolution screens so it’s better than default theme.

Good

A clean, simplified WordPress Admin theme.

Magazi Admin Theme vs Slate Admin Theme