John Galt [EDIT] removed, sponsored

3-columned, search-engine optimized, widget ready, highly customizable WordPress theme with an emphasis on usability.
SEO Blog

Three column gravatar theme with widgetized sidebar and footer, customizable header and with twitter integrated.
GreatIdeas

Three column, fixed width, widget ready theme
TDAge

TDAge is a light-blue two column theme with big, bold feed and “about” images, and large-font headers. TDAge also has easy access links to a blog’s pages and categories from the headers, and has a clean-cut pre-defined template for use as an archive summary page.

(6 votes, average: 4.50 out of 5)

 Loading ...

Garden

Garden consists of a fluid three column outfit with widgetized bars and columns, featuring an custom fields enabled news slider jQuery powered, built in are recent comments with gravatars, related posts, social bookmarking enabled.
The frontpage shows the latest posts followed by footer action. Flickr, Delicio is enabled in the themes options panel.
iEleg

iEleg is a 2 column widget ready wordpress theme. Theme uses 2 small images for faster download. Feel free to get back if you face any problem. I would be very happy to help.
Simple Brown

Two column, widget ready and search engine optimized with a different style for the latest article.
SpotOnSEO

Two Column, fixed width, widget ready, SEO Friendly, AJAX tabbed theme

(4 votes, average: 3.75 out of 5)

 Loading ...

Natureal

3 columns fixed width, widget ready, gravatar ready theme
Vegan

Vegan consists of a fluid two column outfit with eight widgetized bars and columns, built in are recent comments with gravatars, related posts, social bookmarking enabled. Flickr, Delicious is enabled in the themes options panel.
Clockwork2

Two columns fixed width, widget ready, gravatar ready theme
Misanthropic Realm

6 Column consisting of the main content, 2 sidebars and 3 footer sections, widget-ready fixed width theme with minimal images for fast loading and easy customization featuring an author box, author info page, gravatars and highlighted author comments in the comments section along with Custom Archives, Custom Intro Box, Sitemap and full width No Sidebars page templates.
Color Paper

Two column, image rich theme with a stylesheet switcher

(4 votes, average: 5.00 out of 5)

 Loading ...

Contender

Contender is a three column, fixed width, adsense ready theme.
NeeWee

Fixed width, three column, gravatar and widget ready theme.
Pink Orchid

A clean simple SEO optimized three column template in soft pink colors. The theme has two widget ready sidebars, gravatar support and is ad ready. The theme features a bio box that can be edited independently of the side bars and is unaffected by the use of widgets.
Grey Matter

Grey Matter is an two column, gravatar & widget ready, free and easy to use WordPress theme.

(5 votes, average: 2.60 out of 5)

 Loading ...

Fluid Blogging

Fluid Blogging is a very light weight theme, with less than 36KB. It uses almost no images and is fully optimized to make your blog fly like the wind. Fluid width, works fine in resolutions from 800×600 up to 1024×768 pixels, two columns, widget ready, gravatar ready, Adsense ready.
Retro

Back to a time when mainframes ruled the computing world and amber and green CRT’s were the only access to these beasts. Retro is based on the Sandbox theme with the Blueprint CSS framework added to give it a grid design if one chooses to modify the theme to their liking.
Pemuda

Two column, fixed width, widget and gravatar ready theme with inbuilt space for ads.
Aapna Theme

Fixed width, three column theme best for Personal Blog with Dynamically Rotating Album Pictures.

(5 votes, average: 3.80 out of 5)

 Loading ...

Cellar Heat

Dark and light, two column, gravatar ready theme
Glucent

Two column, blue theme with support for FlickrRSS and Page Navi plugin
Classic Modern

A classic old style theme with a modern look. I think the brown color is a symbol of the old and classic style while the blue is the modern color.
Check out more WordPress themes by the same author.
PlainWarrior

PlainWarrior is very simple-looking, clean and elegant two column widget, gravatar and tag ready theme
Fervens Remix

Two column, green and white theme with a wide content column for wide pictures
EcolutionWarrior

Two column widget, gravatar and tag ready theme inspired from the dark side of our environment.
Chrono Press

Three column theme available in ten flavours
Modern Girl

It is a two column, fixed with, widget and gravatar ready, pink and brown theme that uses absolutely no images.
Blue Tech

3 columns, widget and gravatar ready with the middle column for an ad box (eg. 120×600 skyscraper)
Negatendo

Widgetized, gravatar ready, three column theme [...]

(3 votes, average: 5.00 out of 5)

 Loading ...

Decker

Two column, widget ready, gravatar ready theme with a 300×250 AdSense unit integrated on top of the sidebar
Soho
 
Soho consists of a fluid two column outfit with widgetized sidebars and footer columns, built in are recent comments with gravatars, related posts, social bookmarking enabled. CSS drop down menue, flickr is enabled in the themes options panel, tabbed sidebar and extensive footer.
DailyPress

DailyPress comes with widget-ready sidebars, tabbed content, banner ads, minimalistic color scheme and social bookmarking options. The theme is compatible with all versions of WordPress including the latest 2.6 version and has been tested with Firefox, Internet Explorer and Opera.
Firebug

Firebug is a dark (but colorful) theme with two widget-ready sidebars, space for 125×125 banner ads, social tagging options at the end of each post, Gravatar ready comments, feed subscription options, WordPress 2.5+ Gallery feature, and much more.
Gridblog

Gridblog is a fast loading theme (only 36Kb in size) that has very little design [...]

(9 votes, average: 3.67 out of 5)

 Loading ...

Orange

Orange consists of a fluid three column outfit, with widgetized sidebars and footer columns, built in are recent comments with gravatars, related posts, social bookmarking enabled and Flickr is enabled in the themes options panel.
Emphasis

Emphasis is the newest WordPress theme release from Jasonetics. It is a very simple theme, with subtle colors. The posts are bordered with a very light grey, and the links are green and hover orange. This theme is called emphasis because almost all of the focus is on the content and posts.
Helium

Three column, widget ready, gravatar ready theme with ability to post images to index page automatically

(6 votes, average: 4.50 out of 5)

 Loading ...

Blue Grace

Blue Grace is a simple three column WordPress theme with a rotating header image
Fancy

Two column WordPress theme which really lets your blog stand out from the crowd. Make your blog unique by changing the main blog color (pink, yellow, green), background pattern (available over 20 background variations), banner etc through an options page. In addition you have the ability to choose the color of sidebar blocks (violet, yellow, green).
Acosmin v4

Two column, white and grey, gravatar theme with ad ready stops with psd files included
Hello Red

Hello Red is a 2 column red, white, and black, widget ready WordPress theme.
Retrospective

Three column, widget ready, fast loading, search engine optimized theme
 
On the subject of themes, Matt has a tutorial Separating Pings from Comments in WordPress 2.7.

(6 votes, average: 4.17 out of 5)

 Loading ...