@Robert: It is not recommended to remove the Header Logo and Site Title both. So, the best option is to
1. Go to “Appearance => Header” and select your larder header image and then you will see “Crop Header Image Options” and in that you can select all the image area and click on “Crop and Publish” and save changes. See this screenshot http://www.pinterest.com/pin/548594798331307420/
2. Then again go to “Appearance => Header” and in “Header Text” uncheck “Show header text with your image” and save changes. This will remove the site title and description from you header. Now you will only have your header image/logo.
3. Then you want to remove the Header Right Sidebar from “Appearance => Theme Options => Header Options” and select “Disable Header Right Sidebar” and save changes.
4. Now you can simply remove the spaces around your header image by adding in the following css in “Appearance => Theme Options => Custom CSS” box.
#hgroup-wrap, #site-logo { padding: 0; }
The above option is good and best even for SEO purpose. But if you want to do as it is now and just want to remove the spaces. Then you can simply add the following css in “Appearance => Theme Options => Custom CSS” box.
#hgroup-wrap { display: none; }