The blog must be correctly rendered by IE7, IE8, Opera and FF3. Note that we don't impose IE6. If you can make it work for IE6, all the better, but we don't require it.
We're not into having the branding and our logo all over the blog. The blog is intended to be a more relaxed zone where we can talk about the stuff we love to do. Although we'll probably use that space to promote our new products, we'd like people to understand it's first of all a blog where the programmers of the company write what goes through their mind.
Make sure the current posts of the blog "fit" into your design (especially the ones with code and/or images).
Now to the theme.
One of our ideas is to have some sort of theme that looks like the old fashioned XIXth century printed commercials and brochures (Wondermark web site by David Malki can give you an idea of what we mean by that).
The perfect blend of modern structure, old fashioned graphics, typography and talent will lead to a theme we'll love.
The title of the blog "Fresh out of the labs" may give you additional inspiration, especially combined with the above description.
Other ideas we had : Art Déco, Steampunk, Minimalism, "1990 web".
For the rest although snob and obnoxious as all French people, we're very open minded about design and possibilities, so please, surprise us!