The Pure & Simple Wordpress theme is a nice free theme that's easily customized from Styled Themes. We've used it mostly for small businesses wanting a CMS to help them be able to do some of their own updates on it.
The header looks large on the demo because it has a large image of their logo on it. The smaller image, or text you use, the smaller the header will be. I has a really nice nave menu on it. The header is also easy to customize.
Be sure to check out the demo.
You can download it here.