Just replaced the previous theme with this Free Minimalist theme by Blass by 1000ff I love It, you can download it here. To get this theme I installed and removed around 50 themes, and selected 10 best among them, here it goes the 9 clean and Minimal themes.
Upstart Blogger Minim
Upstart Blogger Minim is a Very clean and easy to read theme. It is also ad-friendly, the columns are sized specifically to accept standard ad formats.
Modern Minimal WordPress Theme
Modern is a light, simple and modern theme for WordPress 1.5-2.0. Page links in Modern are layed out horizontally at the top—rather than in the sidebar—creating a clearer distinction between permanent and updated content. For this reason, it is not recommended to use a great number of pages with this theme. Currently, only top-level pages are displayed in the top section—making it possible to exclude pages from appearing there.
Ulap is another free Minimalist theme developed by Val Villar & Dan Matutina
Clean Simple White
Satoshi is a clean and minimal portfolio WordPress theme that’s ideal for showcasing project work.
It comes with a range of professional page templates including a custom front page, a stylish blog design, a portfolio page, and a fully functional contact form.
Cardeo Minimal WordPress Theme
Cardeo Minimal is the first in a series of minimal WordPress themes that I plan to release. Special features include Twitter status integration. NEW Cardeo Minimal is now available as a regular website template too!
Manifest : A WordPress Theme
Manifest if another free publicly available Minimalist WordPress theme
Simple and Minimal. style for print.
No-frills theme for WordPress
No-frills is a legible, uncluttered, minimalist, printer-friendly theme.