BlueGrey is an excellent looking wordpress theme that is completely FREE and highly customizable theme that works straight out of the box. This theme has 2 main columns with sidebar split into 2 more sections. The theme come styled to add the nifty 125px square advertisements that has become a common flare among bloggers of all walk. The theme is easy to use, just upload and activate, then edit the header file (header.php) to include your own description of your blog, that is pretty much it. As for 125px advertisement, it is oddly placed in the footer file (footer.php). Check it out, the theme is undoubtedly top of the line.

Links: Demo | Theme URI