The main purpose of Simple Clean is for it to be crazy simple to get a site up and running in no time. The look and feel of the theme is, as the name suggests, very simple and stripped clean.
Simple Clean is a two column fixed design (optimized for width 960px). The content column have width 610px and right column (sidebar) have width 260px.
News in 7.x-2.0
The 2.0 branch is the HTML5 version of Simple Clean.
- HTML5 doctype and meta content-type
 - Header and Footer sections marked up with header and footer elements
 - Navigation marked up with nav elements
 - HTML5 shim script included for IE compability
 - Css3 Mediaqueries script included for css3 compability
 - WAI-ARIA accessibility roles added to primary elements
 - Nodes marked up with article elements containing header and footer elements
 - Blocks marked up with section elements
 - Sidebar marked up with aside elements
 - Search block form uses the new input type="search" attribute
 - Comments marked up as articles with header/footer elements
 
Changes from 7.x-1.0 is:
- Mission statement is removed from theme settings. For a mission statement. Place a block in the Region Highlighted with a H1 for mission statement.
 - Formating of search results is removed. Use a module like Search Config (http://drupal.org/project/search_config) for more options.
 
News in 7.x-1.0
- New design for tags
 - The 7.x version have links instead of buttons for Read more and Add comments etc.
 - The 7.x version of Simple Clean Theme don't have a ready made subnavigation block built in, instead I recommend the module Menu Block (http://drupal.org/project/menu_block)
 - Do you miss "Mission statement" in D7? In 7.x version of Simple Clean it's back as a optional custom field
 
Features
- 2 column layout
 - 5 regions
 - Tableless design
 - 6.x version includes optional subnavigation in right column for second level primary links
 - Search results with number of hits
 - Typography: Designed for high readability.
 - Primary links as horizontal top navigation
 - Supports secondary links
 - Supports custom logo and favicon
 - Support features like site name, slogan, mission.
 - Supports user picture in profile, comments and post
 - Supports most major features
 - Cross-browser tested in IE6/7, Safari and Firefox
 
Screenshots
Changelog 7.x
7.x-2.0-alpha1 HTML5 version
7.x-1.4 Minor bugfixes
7.x-1.3 Fix for security issue and .info file
7.x-1.2 Fix in the .info file
7.x-1.1 With correct files
7.x-1.0 Whops - 6.x files in initial 7.x-1.0 release  
Developer
Simple Clean is designed and developed by acke (Mattias Axelsson) at Happiness Web Agency.
For news about Simple Clean, follow me on twitter!