I made this suggestion for the Weekly Photo Challenge logo for 2012. They are Public Domain, so feel free to post them on your blog, alter them, print them in your local newspaper or whatever you feel like doing to them.
EDIT: I added these versions with the blue wordpress logo in the center, and cleande them up a little bit. My first versions are at the bottom of the post. Click the images for full size, save on your harddisk & upload to your media library.
And here are the ones I posted in the original post:
You can also use the header. It’s 960×260 pixels.
If you need a logo in a different resolution, just let me know and I’ll resize & post it in the comment section below.
And for all you purists out there, I “made” these (just altered the original WordPress ones):